As one who preaches, I was intrigued by the sermon give by St. Peter as recorded in the Acts of the Apostles. The reading began by saying, "Peter stood up with the Eleven and proclaimed..." All of our preaching today must be "apostolic," or based on the preaching of the Apostles since they were the ones who spent time with the Lord.
Peter's basic message was this: "Let the whole house of Israel know for certain that God has made both Lord and Christ, this Jesus whom you crucified." These were dangerous words for they implied that Caesar was NOT the Lord, a crime for which your life would be taken by the Roman Empire. And in fact that is what Peter and the other apostles suffered. But his preaching "cut to the heart" and caused the people to ask what they should do. Peter was clear as we should be today: "Repent and be baptized." Our life must always be about repentance and conversion, a change of heart.
Finally, Peter said that the people must "Save themselves from the corrupt generation." We too need to proclaim that much of our society is corrupt as well today. So the challenge is given to us. Will we allow Jesus to be the Lord of our lives or we will live as the Masters of our own life?