The defendant appeals his conviction of robbery by intiniidation. Held:

1. The defendant contends that the prosecuting attorney, during his argument to the jury, made an impermissible comment on the defendant’s exercise of his right to remain silent. The proposition is well established that the silence of a criminal defendant can not be used against him at trial. Reid v. State, 129 Ga. App. 660 (5) (200 SE2d 456); Howard v. State, 237 Ga. 471 (228 SE2d 860); Clark v. State, 237 Ga. 901 (230 SE2d 277). It should be noted that defendant was cross examined about not saying anything regarding his version of the event at the time of his arrest. No objection was interposed at that time. See Paschal v. State, 139 Ga. App. 842, 844 (5) (229 SE2d 795). Furthermore, at the time objection was interposed to the prosecuting attorney’s argument, the trial judge directed the prosecuting attorney to discontinue that line of questioning and further directed that the jury exclude such argument from their consideration. Under these circumstances, we find no reversible error. The trial judge did not err in overruling the defendant’s motion for a mistrial.

2. The failure to charge on the law of impeachment of witnesses was not error in the absence of a request. Horton v. State, 120 Ga. 307, 309 (47 SE 969); Tanner v. State, 228 Ga. 829 (8) (188 SE2d 512); Smith v. State, 236 Ga. 5, 11 (222 SE2d 357).

3. The evidence was sufficient to authorize the verdict.

Judgment affirmed.