The ministry of John the Baptist had been predicted in the Old Testament. He was to prepare people for the coming Messiah, who is Jesus. The Jews think they have a good relationship with God just because they are Jews. John the Baptist makes it clear God is not impressed with the fact that they are descendants of Abraham, the father of the Jews. They need to have a heart that is right with God, which should be demonstrated by their behavior. Luke also documents Jesus’ ancestry. The Messiah had been promised to be a descendant of Israel’s ancient King David. This genealogy showed that Jesus is David’s descendent.
Like the Jews, people can sometimes think they have a special relationship with God due to something other than trusting Jesus: being a good person, belonging to a church, participating in certain rituals, or coming from a religious family. God isn’t impressed by any of that. Just like those from the crowd around John the Baptist, we need to be ready to listen to Jesus.