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 a life which was begotten, not made, which has always existed and always will exist. Christ is the Son of God. If we share in this kind of life we also shall be sons of God. We shall love the Father as He does and the Holy Ghost will arise in us. He came into 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 more.
— C.S. Lewis, from Mere Christianity