1John 3:1 says:
The Father (God) has loved us so much! This shows how much he loved us: We are called children of God. And we really are God's children. But the people in the world (people who don't believe) don't understand that we are God's children, because they have not known him (God). (Easy-to-Read Version)
King James Version: Behold, what manner of love the Father hath bestowed upon us, that we should be called the sons of God: therefore the world knoweth us not, because it knew him not.