And now, what does it all matter? It matters more than anything else in the world. The whole dance, or drama, or pattern of this three-Personal life is to be played out in each one of us: or (putting it the other way round) each one of us has got to enter that pattern, take his place in that dance. There is no other way to the happiness for which we were made. Good things as well as bad, you know, are caught by a kind of infection, if you want to get warm you must stand near the fire: if you want to be wet you must get into the water. If you want joy, power, peace, eternal life, you must get close to, or even into, the thing that has them. They are not a sort of prize which God could, if He chose, just hand out to anyone. They are a great fountain of energy and beauty spurting up at the very centre of reality. If you are close to it, the spray will wet you: if you are not, you will remain dry. Once a man is united to God, how could he not live forever? Once a man is separated from God, what can he do but wither and die?
But how is he to be united to God? How is it possible for us to he taken into the three-Personal life?
You remember what I said in Chapter 1 about begetting and making. We are not begotten by God, we are only made by Him: in our natural state we are not sons of God, only (so to speak) statues. We have not got Zoe or spiritual life: only Bios or biological life which is presently going to run down and die. Now the whole offer which Christianity makes is this: that we can, if we let God have His way, come to share in the life of Christ. If we do, we shall then he sharing a life which was begotten, not made, which always has existed and always will exist. Christ is the Son of God. If we share in this kind of life we also shall he sons of God. We shall love the Father as He does and the Holy Ghost will arise in us. He came to this world and became a man in order to spread to other men the kind of life He has—by what I call ‘good infection’. Every Christian is to become a little Christ. The whole purpose of becoming a Christian is simply nothing else.
C.S. Lewis, Mere Christianity (1952; Harper Collins: 2001) 176-177.