To know God is the privilege of a lifetime. To be known by God is the reward of eternity. J. I. Packer says it like this:
What matters supremely is not, in the last analysis, the fact that I know God, but the larger fact which underlies it — the fact that he knows me. I am graven on the palms of his hands. I am never out of his mind. All my knowledge of him depends on his sustained initiative in knowing me. I know him because he first knew me, and continues to know me. He knows me as a friend, one who loves me; and there is not a moment when his eye is off me, or his attention distracted from me, and no moment, therefore, when his care falters.
This is momentous knowledge. There is unspeakable comfort — the sort of comfort that energizes, be it said, not enervates — in knowing that God is constantly taking knowledge of me in love and watching over me for my good. There is tremendous relief in knowing that his love to me is utterly realistic, based at every point on prior knowledge of the worst about me, so that no discovery now can disillusion him about me, in the way I am so often disillusioned about myself, and quench his determination to bless me. (From Knowing God)