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.

 (i) It could mean: since our hearts condemn us and God is infinitely greater than our hearts, God must condemn us even more. If we take it that way, it leaves us only with the fear of God and with nothing to say but: "God be merciful to me, a sinner." That is a possible translation and no doubt it is true; but it is not what John is saying in this context, for here he is thinking of our confidence in God and not our dread of him. 