today I have become Your Father: In the ancient Near East, people often believed in a father-son relationship between gods and kings.
In Israel, the Lord adopted kings as his sons. God set David apart as his most excellent and exalted son (Psalm 89:27). All descendants of David were the Lord’s representatives or agents.
Jesus is an eternal member of the Godhead (the one God who exists as Father, Son, and Holy Spirit; John 1:1). He is also a descendant of David (Acts 13:33; Hebrews 1:5; 5:5). Because he is both eternal and from David's family, Jesus uniquely fulfills God’s plan. He is fully divine and truly human. For this reason, he is rightly called the Son of God.