Albert Barnes Commentary Acts 3:4

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

Fastening his eyes. The word used here denotes to look intently, or with fixed attention. It is one of the peculiar words which Luke uses, Luke 4:20; 22:56; Acts 1:10; 3:12; 6:15; 7:55; 10:4, and others, in all twelve times. It is used by no other writer in the New Testament, except by Paul twice, 2 Corinthians 3:7, 13.

Look on us. All this was done to fix the attention. He wished to call the attention of the man distinctly to himself, and to what he was about to do. It was also done that the man might be fully apprised that his restoration to health came from him.