And we are his witnesses of these things; and so is also the Holy Spirit, whom God has given to them that obey him.
Read Chapter 5
John Chrysostom
AD 407
Of what things? Of His having promised forgiveness and repentance: for the Resurrection indeed was acknowledged, now. But that He gives forgiveness, both we are witnesses, and so is the Holy Ghost, Who would not have come down, unless sins had been first remitted: so that this is an indisputable proof.
Great boldness of speech! And the ground of their credibility: And so is also the Holy Ghost, Whom God has given to them that obey Him. Do you observe that they allege not only the Spirit's testimony? And they said not, Whom He has given to us, but, to them that obey Him: therein alike showing their own unassuming temper, and intimating the greatness of the gift, and showing the hearers that it was possible for them also to receive the Spirit. See, how these people were instructed both by deeds and by words, and yet they paid no heed, that their condemnation might be just. For to this end did God suffer the Apostles to be brought to trial, that both their adversaries might be instructed, and all might learn, and that the Apostles might be invigorated to boldness of speech.