Acts 2:37-39

Now when they heard this, they were cut to the heart [with remorse and anxiety], and they said to Peter and the rest of the apostles, “Brothers, what are we to do?” And Peter said to them, “Repent [change your old way of thinking, turn from your sinful ways, accept and follow Jesus as the Messiah] and be baptized, each of you, in the name of Jesus Christ for the forgiveness of your sins; and you will receive the gift of the Holy Spirit. For the promise [of the Holy Spirit] is for you and your children and for all who are far away [including the Gentiles], as many as the Lord our God calls to Himself.” [Is 57:19; Joel 2:32]