Leslie M. Grant · Commentary on the book of Acts

The power of the Spirit of God in this address itself produced serious response among the people. Pricked in their heart, they inquired of Peter and the apostles as to what they should do. Where conscience is seriously affected, the answer is near to hand. First they are to repent, which refers specifically to their previous treatment of their own Messiah; then to be baptized, publicly reversing their previous public rejection of Him. This was important as regards Jews. Gentiles were not told to first be baptized before receiving the Spirit of God (Ch.10:44-48), but were baptized afterward. They had not (as Israel) been guilty of publicly rejecting the promised Messiah, for no such promise had been given to Gentiles. Being baptized to the name of the Lord Jesus, Jews would have their glaring public sins remitted publicly. This outward ordinance only accomplished outward results: it is no proof of a vital inward work of the Spirit of God. Of course, true repentance is a vital work of the Spirit, and this would result in Jews being willing to be baptized. If a Jew would not be baptized one would seriously question whether he had actually repented.