The Jews in the first century were meticulous record keepers, in particular with genealogies. The primary reason this was important was because they were awaiting their Messiah, whom they believed would be a descendant of King David. When we look through the Gospels of the New Testament, we see two different genealogies for Jesus.
In this episode, Kenny explains why there are two different genealogies. The first is recorded in Matthew's Gospel. He wrote to the Jewish people to highlight Jesus' legal and judicial claim to the throne of David, so they would have been concerned with Jesus being the legal heir. The second genealogy we see in the New Testament was written by Luke, recorded in his Gospel, but written to show Jesus' biological relation to King David, as he wrote to a Roman Gentile audience that would not have cared about the Jewish throne nearly as much.