Behold what manner of love the Father has given to us, that we should be called children of God. And that is what we are! The reason the world does not know us is that it did not know Him.
KJV
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.
ASV
Behold what manner of love the Father hath bestowed upon us, that we should be called children of God; and such we are. For this cause the world knoweth us not, because it knew him not.