Peter continues the same message

Peter and John heal a lame man and the crowds are amazed. Yea, I guess they were amazed....wouldn't we be amazed if someone we knew was paralyzed from birth and someone heal them with a word? Look what Peter does; he immediately wants to shift the attention off of himself and make sure everyone knows Who gets the glory and by Who's power the man was healed:

Acts 3:12 So when Peter saw it, he responded to the people: "Men of Israel, why do you marvel at this? Or why look so intently at us, as though by our own power or godliness we had made this man walk?
13 The God of Abraham, Isaac, and Jacob, the God of our fathers, glorified His Servant Jesus, whom you delivered up and denied in the presence of Pilate, when he was determined to let Him go.
14 But you denied the Holy One and the Just, and asked for a murderer to be granted to you,
15 and killed the Prince of life, whom God raised from the dead, of which we are witnesses.
16 And His name, through faith in His name, has made this man strong, whom you see and know. Yes, the faith which comes through Him has given him this perfect soundness in the presence of you all.

After Peter reminds them what they did to The King of kings, he quickly brings them hope by basically saying, "Hey, don't sweat it, you did it in ignorance. Now be ignorant no longer and know how you can be redeemed."

Acts 3:17-19 "Yet now, brethren, I know that you did it in ignorance, as did also your rulers.
18 But those things which God foretold by the mouth of all His prophets, that the Christ would suffer, He has thus fulfilled.
19 Repent therefore and be converted, that your sins may be blotted out, so that times of refreshing may come from the presence of the Lord,

Just as in the previous chapter, Peter is preaching repetance:

Acts 2:38 Then Peter said to them, "Repent, and let every one of you be baptized in the name of Jesus Christ for the remission of sins; and you shall receive the gift of the Holy Spirit.

Peter also makes it clear by Who's power repentance comes from in verse 26:
Act 3:26 To you first, God, having raised up His Servant Jesus, sent Him to bless you, in turning away every one of you from your iniquities."

It seems clear as you read Acts 3 that to those who are truly surrendered to Jesus, He gives what we need to turn away from ungodliness.