The message of the gospel either pricks in the heart or it cuts to the heart. How the heart is affected by the message depends on whether or not the Spirit of God has already changed the heart. If the message pricks the heart, it is because the heart has already been made alive; born again by the operation of the Holy Spirit. But once the heart is pricked, then what? How should we respond? Peter told those on the day of Pentecost what they should do because of the guilt and conviction they felt, and the message is still the same today.