Behold, how great a love the Father has bestowed on us, that we should be called children of God! For this cause the world doesn't know us, because it didn't know him.
John never used the title huios, "son," to describe the relation of Christians to God. He reserved huios to describe the relation of Jesus to God (cf. 1 John 3:2; 1 John 3:10; 1 John 5:2).