Peter healing a lame man is significant for several reasons. First, Jesus healed many crippled persons during his ministry, Mark 2:1-12 for example. Second, he was a well-known beggar who was crippled from birth. People knew he was unable to walk, and that had never walked in his life. He was not paralyzed or injured. Third, and most importantly for the point of Peter’s sermon, that the lame would “leap for joy” was a key expectation of the Messianic age (Isa 35:6). This text is similar to Isa 61:1-2, a text Jesus read in the synagogue at Nazareth and applied to himself (Luke 4). There is continuity between Jesus and his messianic announcement and the apostolic ministry of Peter.
Isaiah 35:4-7 … say to those with fearful hearts, “Be strong, do not fear; your God will come, he will come with vengeance; with divine retribution he will come to save you.” Then will the eyes of the blind be opened and the ears of the deaf unstopped. Then will the lame leap like a deer, and the mute tongue shout for joy. Water will gush forth in the wilderness and streams in the desert. The burning sand will become a pool, the thirsty ground bubbling springs. In the haunts where jackals once lay, grass and reeds and papyrus will grow.
Isaiah looks forward to a coming age when physical infirmities will be reversed and even the desert will be a fertile. In Acts 2 the Holy Spirit is “poured out” on the people, here in Acts 3 the Holy Spirit is healing physical infirmity.
Finally, this is the first time one of the disciples does the same sort of miracle which Jesus did, albeit in the name of Jesus. This sets up a pattern in the book of Acts, as the gospel enters new areas it is accompanied by the power of the Holy Spirit as witnessed by miracles.
Peter calls for the man’s attention and tells him that he has no money for him, and heals him in the name of Jesus. Why does Peter call for the man’s attention? Perhaps there are a lot of people passing through the gate and the beggar is trying to beg from as many as he can.
The man is instantly healed, his ankles and bones are strengthen and his able to stand. Probably the man had stretched out his hands to take some coins from Peter, but Peter grabs his hands and helps him to stand instead. The fact that he is healed fully and completely is indicated that he walks and jumps, praising God (verse 8). The “leaping” for the formerly lame man evokes the Isaiah 35 passage indicating that this is a sign the messianic age is dawning.
This miracle, therefore, draws attention to the fact the messianic age has to some extent begun with the resurrection and ascension of Jesus. The coming of the Spirit on God’s people is like water poured out on a dry and thirsty land. Peter and John are representatives of the Messiah and use this healing to call a large Jewish crowd to repentance.
If this is true, then likely there are other indications the kingdom is coming/present in the ministry of Peter and John in Acts 2-5. What else do you see here that might support this idea?