John Chrysostom

"And when Peter saw them, he answered." Again it is he who acts, and addresses the people. And in the former instance, it was the circumstance of the tongues that aroused them to hearing, now it was this miracle; then, he took occasion to speak from their accusations now, from their supposition. Let us then consider, in what this address differs from the former, and in what it agrees with that. The former was held in a house, before any one has come over, and before they themselves have wrought anything; this, when all are wondering, and the healed man is standing by; when none doubt, as in the other case where some said "These men are full of new wine." At the one, he was surrounded by all the Apostles as he spoke; but at this, he has John alone; for by this time he is bold, and become more energetic. Such is the nature of virtue; once started, it advances, and never stops.

Observe also how it was divinely ordered, that the miracle should take place in the temple, that others also might wax bold, while the Apostles work not in holes and corners, and in secret: though not in the interior of the temple either, where the greater number were.