the only-begotten Son of God, begotten of His Father before all worlds,
ONE OF THE CREEDS says that Christ is the Son of God "begotten, not created"; and it adds "begotten by his Father before all worlds." Will you please get it quite clear that this has nothing to do with the fact that when Christ was born on earth as a man, that man was the son of a virgin? We are not now thinking about the Virgin Birth. We are thinking about something that happened before nature was created at all, before time began. "Before all worlds" Christ is begotten, not created. What does it mean?
We don't use the words begetting or begotten much in modern English, but everyone still knows what they mean. To beget is to become the father of: to create is to make. And the difference is this. When you beget, you beget something of the same kind as yourself. A man begets human babies, a beaver begets little beavers, and a bird begets eggs which turn into little birds. But when you make, you make something of a different kind from yourself. A bird makes a nest, a beaver builds a dam, a man makes a wireless set—or he may make something more like himself than a wireless set: say, a statue. If he is a clever enough carver, he may make a statue which is very like a man indeed. But, of course, it is not a real man; it only looks like one. It cannot breathe or think. It is not alive.
Now that is the first thing to get clear. What God begets is God; just as what man begets is man. What God creates is not God; just as what man makes is not man. That is why men are not Sons of God in the sense that Christ is... They may be like God in certain ways, but they are not things of the same kind. ....
C.S. Lewis, Mere Christianity