Mr. Justice DANIEL

delivered the opinion of the court.

The defendant in error, in a form of proceeding practised in the court of Washington, instituted a suit in the nature of an action of assumpsit against the plaintiff, upon a contract-in writing for building a house. The contract between these parties, which is drawn out' in much minuteness of detail, it is not deemed necessary to set forth here in extenso in order to a correct understanding of the questions of law raised upon this record. Enough for that purpose will be shown in the following extracts from the agreement above mentioned.

After giving the dimensions of the house to be built, tlie con *473 tract proceéds with these stipulations concerning the work to be done, and the compensation to be paid therefor: —

“ House to be built of two stories, with attic chambers above, of first-rate materials throughout, including office and back buildings, and in the best and most modern style, of workmanship, and to be entirely finished and fit for occupation on or before the 15th of December, 1844.

“ For the brick-work throughout, the best hard-burned red brick are to be employed, with sharp river sand and best lime. For the flooring throughout, thé best quality narrow North Carolina yellow heart pme, tongued, grooved, and secret nailed. Roofs to be slated in the best manner. Spouting to be thoroughly arranged, in the least conspicuous manner, so as to carry off all the water that falls on the roofs of the main building,- office, and back buildings. Door and window frames and doors to be. of perfectly seasoned material, warranted not to shrink.”

After a long detail, having reference rather to an enumeration than' to the quality of the several things to be .done in completing the house and offices, the' agreement concludes in these words: — “ That the said William H. Van Burén is to pay to the said William .Digges for the house built and finished as above specified,- the sum of $ 4,600 in gold" or silver current money of the United- States, or its equivalent in bank-notes, in the following manner; viz. $ 1,000 on the 1st day of September ; $ 1000 on the 1st day of October.; $.1,000 on the 1st day of November; and $1,600 on the day-that the house is entirely finished and fit to occupy, provided that it shall not be later than the 25th day of December, 1844; he, the said William .Digges, to forfeit ten per cent on the whole amount, if the said house is not entirely completed and fit to occupy at the. time agreed upon, viz. December 25th, 1844.”

Subsequently, viz. on the 1st day of. September, 1844, the-above agreement was • altered by the parties in the following, particulars, vw “that in place of the attic story with rooms, as specified in .the above contract, William H. Digges is to build a third story, divided arid finished in all respects like the second story”; arid after reciting some directions with respect to divisions and arrangements in this third story, the hew agreement provides for the “ finishing of a garret; to be floored, plastered, and divided as agreed upon, with the necessary stairways, in the best manner and with the.same materials employed in the second story.”

For the work to be performed under this new agreement,' when it should be cotnpleted, the plaintiff in error was to' pay the additional sum of $ 525 ; but no stipulation appears there *474 in as to the time within which this additional work was to be completed.

The plaintiff in error, the defendant below, pleaded the general issue (inon assumpsit), filed a bill of particulars amounting to the sum of $ 707, for moneys paid, expenses incurred, and damage sustained, by reason of the non-performance by the plaintiff of his agreement; and filed also with this bill of particulars a notice in writing, in which the amount of that bill was claimed in diminution of the plaintiff’s demand. Upon the issue joined, the jury rendered a verdict for the plaintiff, for the sum of $ 1,223.21, with interest from the 21st .day of August, 1845, till payment, and for this sum, with the costs of suit, the court gave judgment against the defendant below.

At the trial of this cause, there were nine separate prayers to the court, and nine bills of exceptions sealed to the rulings of the court upon the prayers thus presented to them. Some of these exceptions it will be unnecessary particularly to discuss,

’ as they are clearly embraced, if not within the terms, certainly within the meaning, - of others which were taken. We will therefore examine those exceptions only which.aré regarded as-propounding in themselves some distinct and separate legal principle. '

The first exception by the defendant below, the plaintiff in error-here, is as follows —

“ The plaintiff, in supportof the issue joined upon the plea of non assumpsit, produced and-proved written contracts between the parties, as follows (copied in pages 461 — 463), and further offered evidence tending to prove that .he had executed the work therein stipulated for, and had delivered it to the defendant, who received it without objection. And thereupon the defendant offered to prove, by competent witnesses, that, before receiving said work, and during, the progress thereof, he had objected to the sufficiency of various parts of the same as a compliance with -the contract, and had communicated said objections to the plaintiff, and that there were various omissions of work stipulated to be done, and various "portions of the work contracted for were done in a defective and inferior manner, and not as well as contracted for by the plaintiff, and that some of these-defects were not and. could not be discovered by the defendant, until after the defendant had entered into the possession and use of the house; and the defendant offered to prove, by way of set-off, and having filed a bilí of particulars of said alleged omissions and defects, and given, due notice thereof to the plaintiff, and of his purpose in reduction of. the contract price of the whole work sued for by the said plaintiff, the value of said omissions, and the difference in value between *475 the actual work defectively executed, and that contracted for; to which evidence so offered, or any of it, the plaintiff objected, as inadmissible under the issue, and-the court, on the objection so taken, refused to admit any of said evidence for said purpose.”

The decision of the Circuit Court, rejecting the evidence described and tendered for the purposes set forth in this exception, cannot be sustained upon any sound legal principle.

We are aware of the rule laid down in the earlier English cases, which prescribed that in all instances wherein a party shall have been injured, either by a partial failure of consideration for the contract, or by the non-fulfilment of the contract, or by breach, of warranty, the person so injured could no.t in an action against him upon the contract defend himself by alleging and proving these, facts ; but could obtain redress only by a cross action against the party from whom the injury shall .have proceeded. .This doctrine of.the earlier, cases has been essentially modified by later decisions, and brought by them to the test of justice and convenience, which requires, that whenever compensation or an equivalent is claimed by á party in return for the performance of conditions for which such compensation or equivalent has been stipulated, the person so claiming is bound to show a fulfilment in good faith of those conditions; and the party against whom the claim shall be made shall be permitted to repel it by proof of an entire failure to perform, or of an imperfect or unfaithful performance; or by proof of injurious consequences resulting from either of these delinquencies; and shall not be driven exclusively to his cross action. Of this doctrine the following examples, amongst others to be. found, may be adduced from the-English courts.

Per Parke, Justice, in the case of Thornton v. Place, 1 Moody & Robinson, 219, it is said: “ When a party engages to do certain work on certain specified terms, and in a specified manner, but in fact does .not perform the work so as to correspond with the specification, he is riot of course entitled to recover the price agreed upon in the specification; nor can he recover according to the actual value of the work, as if there had been no special.contract. What the plaintiff is entitled to recover is the price agreed upon, subject to a.deduction, and the measure of that deduction is, the sum which it would take to alter the work so as to make it correspond with the specification.”

In Chapel v. Hicks, 2 Carrington & Marshman, 214, it is said: “ In an action on a special contract for work done under the contract, and for work and materials generally, the defendant may give iri evidence ■ that the work has been done im *476 properly, and not agreeably to the contract; in that case, the plaintiff will only be entitled to recover the real;value of the Work done and materials supplied.”

In the case of Cutler v. Close, 5 Car. & Payne, 337, where a party had contracted to supply and erect a warm-air apparatus for a certain sum, it was ruled, in an action for the price (the defence to which was, that the apparatus did not answer), that, if the jury thought it was substantial in the main, though not quite so complete as it might be under the contract, and could be made good at a reasonable rate, the proper course would be to find a verdict for the plaintiff, deducting such sums as would enable the defendant to do what was requisite. And Tindal, C. J., in his instructions to the jury, uses this language: “ The plaintiffs say that they have performed their contract, and are entitled to be paid. On the contrary, the defendant says that the apparatus is not at all of the sort he contracted for; and therefore he is not liable to pay for it. The law on the subjeet, as it seems to me, lies in a narrow compass., If the stove in question is altogether incompetent, and unfit for the purpose, and either from that, or from the situation'in which it is placed, does not at all answer the end for which it was intended, then the defendant is not bound to pay. If it is perfect, and the fault lies in management at the chapel, then the plaintiffs will be entitled to recover the whole price. But there is another view of the case. The apparatus may be in the main substantial, but not quite so complete as it, might be according to the contract; and in that case, if it can be made good at a reasonable expense, the proper course will bej to give your verdict for the plaintiffs, deducting such sum as will enable the defendant to do that which is requisite to make it complete.”

But, as conclusive with this court upon this point, it may be ■ remarked, that it was carefully considered at the last term in the case of Withers v. Greene, 9 Howard, 213; the decisions applicable thereto from the courts both in England and the United States were then collated and- examined, and upon that examination the doctrine herein above propounded received the concurrence of all the judges. Again expressing our approbation of this doctrine, we conclude that the proof tendered, as declared in the first exception of the defendant below, should have been admitted, and that the Circuit’ Court erred in ruling, its exclusion from the jury.,

The second exception by the defendant states, that, in addition .to the evidence previously tendered by him, he offered proof tending to show the peculiar adaptation of the house contracted for, both in its design and situation, to the defendant’s personal and professional pursuits and convenience, and *477 that the amount of ten per centum on the contract price stipulated to be forfeited if the house was not entirely, finished and ready for occupation, as therein provided, on the 25th of December, 1844, was intended by the parties--as and for liquidated damages, that would result and fairly belong to the said defendant by reason of said failure to finish the said house on the 25th of December, 1844; and that the court refused to hear the evidence thus tendered. In the refusal of the court to admit the evidence thus tendered we think they decided correctly. It would have been irregular in the court to go out of thé terms of the contract, and into the consideration of matters wholly extraneous, and with nothing upon the face of thewriting pointing to such matters as proper or necessary to. obtain its construction or meaning. The clause of the contract. providing for the forfeiture of ten per- centum on the amount of. the contract price, upon a failure to complete the work by a •given day, cannot properly be regarded as an agreement or settlement of liquidated damages; The terrp. forfeiture imports • a penalty ;■ it has no. necessary or natural connection with the measure or degree of injury which may result from a-breach of contract, or from an imperfect performance. It implies ati absolute infliction, regardless of the nature and extent of the causes by which it is superinduced. Unless, therefore, it shall have been expressly adopted and declared by the "parties to be a measure of injury or compensation, it is never taken as such by courts of justice, -who-leave it to be enforced where this can be done in its real character, viz. that of a penalty. In a defence like-that attempted by the defendant in the Circuit Court, upon the essential justice and fairness of .the acts of the parties, a positive immutable penalty could hardly be applied as a fair test of their' merits.

In the third exception by. the defendant, it is" stated'that the plaintiff, having given evidence to show that the defendant, whilst the house in question was being built, made a contract, for an alteration in the style and finish of the plastering of the house, with a third person, and not with the plaintiff; and thereby the execution of the work on the said building was delayed beyond the 25th of December, 1844; the defendant . offered evidence tending to prove that the,said plastering and the style and finish thereof were usual and proper and necessary to the completion of the said house; and further offered to prove, that, at the time of the execution of the said plastering, the defendant in the presence of the plaintiff insisted on' and required him to execute the sanie as a part of his contract; and that he refused so to do, and that to the admissibil-. ity of this evidence, objection "being made, it was excluded *478 •from' the jury by the court. In this decision the court were certainly correct.- The defendant could- have-no right to insist upon the performance of plastering, or of any other description of work, unless it came within-t-he provisions of the contract; the simple fact that the work - demanded, was suitable to the' style of the defendant’s house, could give him no right to demand its execution, unless the plaintiff had contracted-for its. . performance. It was incumbent, therefore, on the defendant, to prove by legal evidence that the work demanded by him was within the provisions of the contract; but instead of doing this, he insisted upon showing merely that he, the defendant, had determined this work to be proper and within the,pro-, visions of the contract, and that the plaintiff’s non-concurrence in this determination, and consequent refusal to do what the defendant required, were to be received as proof of a failure on the part of the plaintiff to perform his contract ;> an 1 as forming a just ground with the defendant for his resistance, to the' action. It would' indeed have been -strange, if the court could have tolerated such an irregularity as this; by which the defendant would have been permitted to become a witness in his own behalf.

The fourth and fifth exceptions on the part of the defendant below, relating merely to the admissibility ■ of testimony to show a failure to perform, or an incomplete performance, on the part of the plaintiff, are embraced within the first exception already considered, and the rulings of the court as to these two last instances being in contravention of our opinion as declared upon the first exception, are pronounced by this court to be erroneous.

In the- sixth exception of the defendant, two subjects essentially distinct in character are blended. As to the first, it is stated that the plaintiff, having further given evidence tending to show that, after the plastering of the house was begun, the' defendant entered into a contract with the plasterer to make cornices and centre-pieces for the parlors and passages; that a delaji in the work, for- a week was occasioned by the negotiation leading to the said agreement; and a further delay of two weeks by the additional plastering, and part of the same being frozen, insomuch that the plasterer could not finish the work until some -days after the. 25 th of .December, 1844, and much of the' carpenters’ wqrk ' and- the:--painters’ was thereby postponed .and delayed until after ihe said day; and the said defendant theff'gáve evidence to .show that the plaintiff knew- of the said agreement for the- said additional plastering, and did .not object thereto. ■ And thereupon the- defendant prayed the court-to instruct1’the jury7, that-if they shall find that.any delay *479 was caused in completing the work in consequence of the ex* tra plastering in the parlors and passage, done under the dis'tinc-t contract therefor given in evidence, and they shall further find that said extra plastering was so done with the full knowledge* and sanction of the plaintiff, and without any understand-, ing between him and the defendant at the time, that in consequence thereof a further time should be allowed for completing the building, then the plaintiff is not entitled to any further time for completing the building because of such work, and the delay attending the same.

The second subject embraced in this exception is the.forfeiture of ten per centum upon the contract price of the work, >v.hich the court was asked to declare was the amount of liquidated damages, the whole amount of which on the price of the work the defendant was authorized to claim for a failure to complete the work by the- 25th of December, 1844, unless the jury should find that the failure to complete. the work proceeded wholly from the acts or default of the defendant. The refusal by the Circuit Court of both the instructions appearing upon this exception is entirely approved.

It is difficult to conceive, upon what ground the defendant could be permitted to interpose an obstruction to the fulfilment of the contract, and then to convert that very obstruction info a merit on his own part, or into the- foundation of a claim against the party-whom he had already subjected to the inevitable consequences of the obstruction so interposed; an inability to comply with his engagement, ahd a postponement of the fruits of a compliance therewith, if that had been permitted. Mere acquiescence in this irregularity by the plaintiff should not subject him to farther mischief. With respect to the second subject embraced in this exception, vik. the forfeiture of ten per centum claimed by the defendant, we deem it unnecessary to add to what has been already said on that subject. We will here remark, once for all, with respect.to this penalty, that, as it constitutes the only ground for the. eighth and ninth exceptions taken by the defendant below, those exceptions must be regarded as expressly overruled.

" By the' seventh exception of the defendant below, it appears that the court were asked to propound as the law, that if, from the evidence, it should appear that the plaintiff contracted with ■the defendant in Writing, to build, complete, and deliver the said house, to him on or before the 25th day of December, 1844, and that the plaintiff failed to do so; .and the jury shall find that the time for said completion and delivery was-not extended beyond the said 25th of December, 1844, by the agreement of the said plaintiff and defendant, or by the act of the *480 defendant, then the plaintiff is not entitled to recover in this action, which instruction the court refused to give.

The ruling of the court, as set forth in this exception, though not reconcilable 'with their own decision on the first prayer presented to them by the defendant, is in accordance with the opinion we have expressed in reference to the questions raised by that prayer, and also with the doctrine ruled by this and in other tribunals upon those questions, as in treating of that first prayer we have already shown. It places the parties upon the true ground of contestation between them, viz. the truth, the extent, and manner of performance on the one hand; the degree of injury, from omission, neglect, or imperfection of performance on the other. The ruling of the Circuit Court, therefore, upon this exception, is' entirely approved; but as that court has erred in its decision in reference to the prayers in the first, ' fourth, and fifth exceptions of the defendant, its decision as to those prayers is hereby reversed, with costs, and this cause is remanded to the Circuit Court, with orders for.a venire facias for a new trial in conformity with the principles expressed in this opinion.

Order.

This cause came on to be heard on the transcript of the record from the Circuit Court of the United States for the District of Columbia, holden in and for the County of Washington, and .was argued by counsel. On consideration whereof, it is now here ordered and adjudged by this court, that the judgment of the said Circuit Court in this cause be, and the same is hereby, reversed, with costs, and that this cause be, and the same is hereby, remanded to the said Circuit Court, with directions to award a venire facias de novo.