ACTS 2 IS SOMETIMES CALLED the birthday of the church.
This can be misleading. There is a sense in which the old covenant community can rightly be designated church (Acts 7:38 — "assembly" in NIV). Nevertheless there is a new departure that begins on this day, a departure bound up with the universal gift of the Holy Spirit, in fulfillment of Scripture (Acts 2:17-18) and in consequence of Jesus' exaltation "to the right hand of God"(2:33). The critical event that has brought this incalculable blessing about is the death, resurrection, and exaltation of Jesus Christ; this even was itself foreseen by earlier Scripture.
One of the things that is striking about Peter's address, quite apart from its comprehensiveness, courage, directness, and passionate fire, is the way the apostle, even at this early stage of his post-resurrection public ministry, handles what we call the Old Testament Scriptures. His use of Scripture in this Pentecost sermon is too rich and variegated to unpack in detail. But observe:
(1) Once again there is a David-typology (Acts 2:25-28, citing Ps. 16:8-11). But here there is also a small sample of apostolic reasoning in this regard. Although it is possible to read Acts 2:27 ("you will not abandon me to the grave, nor will you let your Holy One see decay") as David's conviction that God will not, at that point, let him die, the language is so extravagant, and David's typological role so common, that Peter insists the words point to something more: a greater than David will quite literally not be abandoned in the grave, and will not be permitted to experience decay. David, after all, was a prophet. Whether in this case, like Caiaphas (John 11:50-52), David spoke better than he knew, at least he knew that God had promised "on oath that he would place one of his descendants on his throne" (Acts 2:30).
(2) The prophecy of Joel (Acts 2:17-21; see Joel 2:28-32) is more straightforward, in that it is a case of verbal prediction and does not resort to typology. The obvious meaning is that Peter detects in the events of Pentecost the fulfillment of these words: the "last days" (Acts 2:17) have arrived. "Whether the sun turning to darkness and the moon turning to blood were both events bound up with the dark hours when Jesus was on the cross, or an instance of Hebrew nature symbolism, need not detain us here.) This Old Testament passage is one of a handful of texts that predict the coming of the Spirit, or the writing of God's law on our hearts, but in any case covenant-wide personal transformation in the last days (e.g., Jer. 31:31 ff.; Ezek. 36:25-27).
Joshua 22; Acts 2; Jeremiah 11; Matthew 25