You men of Israel, hear these words; Jesus of Nazareth, a man approved of God among you by miracles and wonders and signs, which God did by him in the midst of you, as you yourselves also know:
All Commentaries on Acts 2:22 Go To Acts 2
John Chrysostom
AD 407
Men of Israel:
it is not for flattery that he uses this term; but, as he has borne hard upon them, he relaxes a little, and puts them in mind of their great ancestor Israel.
a man confirmed by God:
Observe; what great matter was this, to say that He was sent from God? For this was the point which on all occasions both He and John and the Apostles were studious to show. Thus hear John saying: The same said unto me On whom you shall see the Spirit descending, and abiding on him, this is He. John 1:33 But Christ Himself does this to an extreme; Of Myself I am not come, He sent Me. John 7:28 And everywhere in the Scriptures this seems the point most studiously insisted upon.
just as you also know:
He calls themselves as witnesses.