1.4.2 Belief in God, the Son
With the incarnation of God, the Son, the Old Testament promises pointing to the coming of the Messiah were fulfilled. Jesus Christ gives the exhortation: "You believe in God, believe also in Me" (John 14: 1). Thus belief in God as revealed in His Son was also required in addition to belief in God as the omnipotent Creator of heaven and earth, who had made a covenant with the people of Israel. The faith that is now required also entails keeping the word of Jesus Christ (John 8: 51; 14: 23).
In the old covenant, the term "God, the Father" expressed God's care for His people. Through Jesus Christ, however, it becomes evident that God is the Father of the only-begotten Son from eternity.
Jesus Christ opens up the way for human beings to attain childhood in God and to be called as firstlings (see 10.1.3￫), through the rebirth out of water and the Spirit, that is by receiving Holy Baptism with water and Holy Sealing. These two prerequisites are not contingent on being a descendant of Abraham, but on believing in the Saviour and receiving all of the sacraments (Romans 3: 22, 29-30; Ephesians 2: 11-18). Being caught up to the Lord at His return is the direct expression of becoming a firstling. Firstlings are guaranteed direct fellowship with God eternally.