Claim. Jesus’ declaration of God as “Father” was a world-historical breakthrough — replacing the OT image of a God of judgment and law with the God of love, and elevating fallen humanity to the position of adopted child.
Elaboration. “On leaving the Old Testament Age … Jesus declared God as the Father and elevated fallen people to the position of adopted child in order to bring them into a parent-child relationship with God … the establishment of the parent-child relationship with God was a heavenly secret that could be accomplished by no one other than Jesus” (3.2.-the-adopted-child-can-call-out-father, 35-276, 1970.10.25). Moses could introduce only God’s authority and power; Jesus introduced love. The priests heard “Father” as blasphemy — proof of how radical the shift was. Through Jesus, the invisible God became visible: “I am in the Father and the Father is in me” (John 14:10-11, cited ibid, 4-308, 1958.10.5).
See also. csg-jehovah-was-an-angel-not-god, csg-nt-believers-as-adopted-children