John Calvin Commentary Acts 3:4

"And Peter, fastening his eyes upon him, with John, said, Look on us." — Acts 3:4 (ASV)

Look upon us. Peter does not speak this way before he is certain of God’s purpose and intent. And surely, in these words, he commands him to hope for some unique and unusual benefit. Yet, a question may be raised here: did they have the power to work miracles whenever they wished?

I answer that they were ministers of God’s power in such a way that they attempted nothing of their own will or initiative. Instead, the Lord worked through them when He knew it was fitting for it to be so. This is why they healed one person and not all. Therefore, just as in other things, they had the Spirit of God as their guide and director, so also in this matter.

Consequently, before Peter commanded the lame man to arise, he cast and fastened his eyes upon him. This steadfast gaze upon him was not without some particular prompting of the Spirit. This is why he speaks so confidently (and securely, without any fear) about the miracle. Furthermore, by this statement, Peter intended to prompt the lame man to receive the grace of God, even though the man was expecting nothing but alms.