vv 22-23 God removed Saul and replaced him with David, a man about whom God said, ‘I have found David son of Jesse, a man after my own heart. He will do everything I want him to do.’ And it is one of King David’s descendants, Jesus, who is God’s promised Saviour of Israel!
At the very beginning of his missionary travels Paul finds himself in Antioch and speaking in the Jewish synagogue. He wanted to speak about Jesus but started at a point the Jews would be able to say ‘Ah, we know what he is talking about.’ He gave a potted history of the nation, easily grasped by his hearers. Just to mention David was to bring people on side with him and following the tale. From Saul and David he leaps on 1,000 years to Jesus who is introduced as a descendant of David. That would have been sufficient to authenticate Jesus as a genuine Jew and therefore worth thinking about. Paul moved on immediately to speak about the death and resurrection of Jesus. You can read the whole story about the beginning of the church in Antioch in this chapter 13 in Acts.
In his Gospel, Matthew lists David as one of the lynchpins in Jewish history (Matthew 1:17). And the reason – more than any other person David is cited as a man after God’s own heart. Along with Abraham he is regarded as one of the founding fathers of the nation of Israel.