What does Acts 3:4 mean?

Peter and John are entering the temple when a lame man asks for alms. Peter doesn't have any money—what he has is much more valuable. But first, he needs the man's attention.

Many times, Jesus preferred His miracles remain quiet. Sometimes, however, He gathered people's attention. This was the case with the woman who had the issue of blood. A woman who had been bleeding for twelve years had the boldness to touch Jesus' robe. She realized immediately she was healed and meant to sneak away, but Jesus stopped her and called the crowd's attention to her. In doing so, He publicly commended her faith and let her community know that she was no longer unclean (Mark 5:25–34).

Whether or not a miracle-worker intended for his work to be public depended on the situation and the purpose of the miracle. In this case, Peter is having pity on a lame man, but his main purpose is to use the miracle to bring attention to Jesus. Peter could have quietly healed the man and gone about his business. That would not have provided him a chance to be Jesus' witness in front of the crowd (Acts 1:8).

This dichotomy is seen in Jesus' teaching about ministering to others. In Matthew 6:3–4, He says to give to the needy secretly so that your reward comes from God, not other people. But in Matthew 5:14–16, He says to let others see your good works. These are not at all contradictory, because of the difference in who will receive the praise. If your good works inspire others to give God glory, "let your light shine" (Matthew 5:16). Since Peter's goal is to teach about Jesus, he allowed the miracle to be public.