Why is there Christ?

In Mere Christianity, CS Lewis asks us to consider why there is Christ. God could be Spirit all by Himself. But could God be Love without something to love? This is what Lewis poses in his chapter “Good Infection,” and it has the ring of truth. God, not trying to hide Himself but ever seeking to reveal Himself, has to have an expression, some way to express love. Lewis writes:  “…we must think of the Son always, so to speak, streaming forth from the Father, like light from a lamp, or heat from a fire, or thoughts from a mind. He is the self- expression of the Father—what the Father has to say. And there never was a time when He was not saying it.” (from Power of Yielding)