God IS love (1 Jn 4:16) - the only attribute with which God is defined in such an absolute way. Love sums up all his other attributes. It is the deepest essence of who God is; it speaks of him more clearly than any other characteristic.

What does it mean that God is love? Jesus said, "As the Father has loved me, so I have loved you" (Jn 15:9). Not just "as much as" but "as." How has the Father loved Jesus? By completely pouring himself out for his Son in infinite self-emptying love, for all eternity. It is this eternal drama of love that was made flesh in space and time by Christ's incarnation, death and resurrection. "Greater love has no man than this, that a man lay down his life for his friends" (Jn 15:13). This is the mystery at the heart of who God is.