Romans 1:3

3-4 This good news is about God's Son, who is Jesus Christ, our Lord. Jesus was born as a human baby, a descendant of King David. But after Jesus died, God's Holy Spirit raised him to make him alive again. In this way God showed clearly that Jesus was his powerful Son.

1:1Christ is a name for Jesus in the Greek language that means the same as Messiah in the Hebrew language. It means someone that God chose as a special king for his people.
1:3-4David was a great king of Israel, about 1,000 years before Jesus lived on earth.