Peter took the man by his right hand and helped him up. As he stood, the man's feet and ankles were instantly strengthened and healed. The man jumped up, stood, leaped praising God, and walked into the Temple with Peter and John.
People continually gave the man money day after day. God, through Peter, gave the man his life back so he could earn his own wages and perhaps be more prosperous and not be in need daily. This might be a great lesson. We may be in a particular situation such as the lame man. In his position we might pray that many people came to temple each day and would feel generous. We may pray hoping to get a day's earnings. God may have so much more in store for us, such as a full recovery and a better life than we have ever had. God, through Peter said, I don't have what you are asking for, I have so much more.
He may just be saying something similar to us. I hear your prayers for a better job, nicer house, a wife or husband. But I have so much more. I have salvation and eternal life for you through faith in the name of Jesus Christ. Through faith in Him as Messiah you will not hurt, have no pain, not suffer, or be in need - ever. Through Jesus, you will be given more than you have asked. You will be given life eternal in the presence of God, Himself.
As they walked through the Temple, people recognized the lame man and were amazed. They all rushed out to where the man, Peter, and John were. As a crowd gathered, Peter saw the opportunity to speak to them. He asked them why they looked at him and John as if they had done something amazing by their own power. Peter proclaimed it was the God of Abraham who had done this thing. God brought glory to Jesus by Peter using the name of Jesus to heal the man. And by the healing done in the name of Jesus, it also brought glory to God. (Back in John 17:1, Jesus prayed "Father, the hour has come. Glorify your Son so He can give glory back to you." This is a perfect example of that happening.)
Peter continued by saying he was talking about the very same Jesus they handed over to Pilate. You rejected His holiness and demanded a murderer be set free instead of Jesus even though Pilate found Jesus not guilty of anything. He told them they were responsible for the killing of Jesus but God raised Jesus from the dead and told them they had actually been witnesses of Jesus being alive.
Peter explained that the man had been healed by faith in the name of Jesus and faith in His name is what healed the man right in front of them. I think faith was exhibited in several ways. Peter was able to help the man because, he himself, had faith that the name of Jesus would heal. The man had faith that Peter knew what he was talking about. Because of the faith Peter had in the name of Jesus, the man also had faith in Jesus name and knew he would be healed.
Sometimes I read these stories of great faith and wonder how I would behave in such a situation. Would I completely give myself over to faith or would I hold back a little? If I was to hold back a little, why would I do that? Could it be I might be afraid I might appear foolish giving myself completely in faith to something that didn't work out? However, if I was to hold back then I might look wiser in case nothing happened. Could it be pride that keeps us from having complete faith? The sad part is, not completely being given in faith is just what makes things not happen. In an effort to protect a little bit of pride, we may actually be sabotaging the very thing we want to happen.
Peter told them he believed their killing Jesus was done in ignorance. In those events, the word of the prophets was being fulfilled regarding the Messiah. Jesus had to suffer as it was written. That being said, Peter told them it was time to repent of their sins now and time to turn to God so their sins could be wiped away. He promised a time of refreshment which would come by the presence of the Lord who will again send Jesus the Messiah.
Jesus had to stay in heaven until the time of final restoration of all things as God promised long ago through the prophets. Even Moses advised that anyone who would not listen to "that Prophet" referring to Jesus as the new prophet of God, would be cut off from God's people. Peter said, just as Moses was a prophet speaking as God directed and also the one through whom God brought deliverence to all Israel when in captivity, Jesus would be the one who God used to proclaim the plan of redemption offered by God, again bringing deliverance.
From Samuel on, every prophet spoke about what was happening right then. He told the crowd they were all the children of those prophets and are included in the covenant God promised to their ancestors. Their ancestor here is Abraham. As is written in the book of Genesis, Abraham had just taken his son, Isaac to be sacrificed by his own hand as God directed. Abraham trusted God and had complete faith in God, therefore in obedience to God's request, he prepared an altar to sacrifice Isaac. Of course, we know God did not let him sacrifice Isaac. God responded to Abraham's obedience in Genesis 22:15-18 which is the covenant, or promise, God made to Abraham. This is the covenant Peter told the crowd they were included in. Genesis 22: 15-18; "The angel of the Lord called to Abraham from heaven a second time and said, "I swear by Myself, declared the Lord, that because you have done this and not withheld your son, your only son, I will surely bless you and make your descendants as numerous as the stars in the sky and as the sand on the seashore. Your descendants will take possession of the cities of their enemies, and through your offspring all nations on earth will be blessed, because you have obeyed me."
Peter explained that God had sent Jesus first to all the people of Israel. Jesus' mission was to turn Israel from their sinful ways, thus bringing blessing to them all. As we end chapter 3 Peter is still addressing the crowd but at the start of chapter 4 we find Peter being confronted by the religious leaders.