Albert Barnes Commentary Acts 22:20

"and when the blood of Stephen thy witness was shed, I also was standing by, and consenting, and keeping the garments of them that slew him." — Acts 22:20 (ASV)

The blood of your martyr Stephen was shed (Acts 7:58; Acts 8:1).

I also was standing by (Acts 7:58).

And consenting to his death (Acts 8:1).

And kept the raiment (Acts 7:58). These were the outer robes or garments, which were usually laid aside when they engaged in running or labour.

All this showed that, although Paul was not engaged in stoning Stephen, he was with them in spirit and fully accorded with what they did.

These circumstances are mentioned here by him as reasons why he knew that he would not be received by Christians as one of their number, and why it was necessary, therefore, for him to turn to the Gentile world.