This begins our studies on the first sermon ever preached by a Christian. Peter employs the principle of heraldic pronouncement, a proclaiming of the facts, things which couldn't be doubted or questioned, to give his message of Good News and this type of preaching is used throughout this book and the New Testament. So, Peter announces himself, answers the immediate question of the apostles' drunkenness and reveals that the prophecy of Joel was directly connected to what had happened that very day! In talking about this, Peter speaks of 'the day of the Lord' and it is important for us to know more about what Jews thought of this day. They never had lost the conviction that they were God's chosen people and they had their historical back story as evidence. It was clear that they would never reach their aspirations of special privilege amongst other nations by human effort alone. They looked to God to intervene directly in history and give them the place they expectantly dreamed about. The day of that intervention they called, 'The Day of the Lord'. Jewish people divide time into two ages: the present, utterly evil age, full of suffering; and there was the age to come, the golden age of God. Bringing that second age in would be the Day of the Lord, which might appear terrible at first. There are descriptions of this day to be found in many of the writings of the Prophets: Isaiah- 2 v 12; Amos-5 v 18-20; Zephaniah- 1 v 17; Joel 2; and so on. Also, references to it can be found in Paul's first letter to the Thessalonians-5 v 2-11, and Peter's second letter-3 v 10.
Peter is thus saying to the Jews: ''For generations, you have dreamed of the day of God and now in Jesus, that day has come.' In Jesus, God arrived in person into human history!