It is only through the Holy Spirit that Peter was able to preach words with such power and of great eloquence. So much of what we might well think would take decades to work through concerning the divinity of Jesus Christ are here complete already!
1. Remind yourself that Peter is speaking to Jews here. He uses the Old Testament to substantiate his claims that Jesus was the long-awaited Messiah. He quotes from two of the great patriarchs, Moses and Samuel, in building his case.
2. He declares that his listeners had sinned greatly in calling for the crucifixion of Jesus, but they can be excused because their ignorance had caused them to act in this way. He intends that his words will enlighten them, so they can grasp hold of the Truth in Jesus Christ, but their ignorance can no longer be an excuse. If they do not accept Him then they will be condemned.
3. Peter declares all this as an urgent matter, because Jesus is returning. Time unknown, but in his eyes this makes it all the more to be expedited, because that time could be tomorrow!
4. The demand for listeners is to repent and turn themselves towards God: accept what He is offering, an opportunity to start life anew: ''You must be born again!'' Jesus declared to Nicodemus.
5. Peter reminds his listeners of the special privilege which is theirs as Jews and how that brings with it a special responsibility. You have the opportunity first, he declares, in a short time the Early Church will be almost all Gentiles, because you reject the Good News of Jesus Christ!
6. He balances grace and truth in his words in imitation of His Master.