There is an extraordinary, powerful and multi-dimensional Christological focus to Peter’s preaching. At a trivial level, Peter’s speech talks about Jesus a lot—but it is worth pausing to see exactly how he understands him. First, it is Jesus, in his death and resurrection, who has brought about the fulfilment of God’s purposes as set out in Scripture. Second, the climax of all that has happened is the ascension—Jesus is now seated at the right hand of the Father, and it is to this reality that we must respond. Thirdly, this means that Jesus is now Messiah (the fulfilment of the hope of Israel) and Lord. But earlier, the ‘Lord’ is Yahweh, the God of Israel—now Jesus shares in this title, and he is the Lord whom the people call on to be saved. Again, we find this incorporation of Jesus into the person of the God of Israel, creating a kind of Christological monotheism, all through Paul’s theology, from his adaptation of the Shema in 1 Cor 8.6, through his identical use of Joel 2 in Romans 10.13, to his application of the monotheism of Isaiah to Jesus in his ‘Christ-hymn’ in Phil 2.9–11.
Luke reinforces this Christological focus in the very way he structures his summary of Peter’s speech. The late Martyn Menken observed:
There are also several instances of isopsephia in Acts, where the number of syllables of an episode or speech is equal to the numerical value of an important name or word occurring in or related to the passage in question (such as we found concerning John 1.1-18, where both the number of syllables and the numerical value of monogenes are 496). Peter’s speech in Acts 2.14-b-36 is made up of two equal halves: 444 syllables in 2.14b-24, and again 444 syllables in 2.25-36. Their sum, 888, is the numerical value of the name Iesous, a number which was famous in this quality in the second century, witness Irenaeus’ Aversus Haereses 1.15.2.
We also need to note that, in a Christian theological context, we consider the Holy Spirit the third ‘person’ of the Trinity. But in Peter’s context, and the understanding of those he is listening to, the Spirit is simply the presence and power of God himself at work amongst his people. If Jesus is the one who is able to dispense the Spirit (as Peter claims), then Jesus is the one who mediates God’s own presence and power, again assuming Jesus is incorporated into the person of God himself.