The specific concept of God as Father
What is decisively new in the Christian, New Testament faith in God lies in the fact that this faith is so closely bound up with the person, teaching, and work of Jesus Christ that it is difficult to draw boundaries between theology (doctrines of God) and Christology (doctrines of Christ). The special relationship of Jesus to God is expressed through his designation of God as Father. In prayers Jesus used the Aramaic word abba (“father”) for God, which is otherwise unusual in religious discourse in Judaism; it was usually employed by children for their earthly father. This father–son relationship became a prototype for the relationship of Christians to God. Appeal to the sonship of God played a crucial role in the development of Jesus’ messianic self-understanding. According to the account of Jesus’ baptism, Jesus understood his sonship when a voice from heaven said: “This is my beloved Son, with whom I am well pleased.” In The Gospel According to John, this sonship constitutes the basis for the self-consciousness of Jesus: “I and the Father are one” (John 10:30).