God is love by essence. That is to say, love is forever and unchangeably essential to his existence as God. He was not at first, as some may be led to suppose, a mere percipient being, having all knowledge, who formed conjecturally an idea of love, came to the conclusion that it was a good and desirable thing, and then added it as an accessory to his original existence. On the contrary, God always had a heart; always had a true and effective sensibility, operating, by an eternal law of action, in the line of right and goodness. And if, by universal consent, the heart takes the precedence of the head, — if no greatness of intellect can elevate and save a man who has evil and depraved affections, — then God cannot be what he is, the infinitely desirable and infinitely good, without love as the central and leading element, the basis and the completion of his character.
— adapted from A Treatise on Divine Union (1851) Part 4, Chapter 2.