In Jesus we have one who, of course, owes his being to the Father, but one who is not created but loved into existence; for, of course, it is not that the Son first exists and then is loved by the Father, his divine existence is for him eternally to be loved by the Father. This is what Jesus announces to us: that the very centre and heart of his being is his being loved by the Father, he exists only in this relationship to the Father. When he searches into his own identity, when he asks himself “Who am I?” he finds that the ultimate thing about him is the Father’s love. And by grace, by our receiving the Holy Spirit, by our sharing in the death and life of Christ, this becomes the ultimate thing about us too. Not that we are created, but that we are loved. We are not objects of the Godhead, but, by being in Christ, we are within the Godhead.
The difference between our divinity, our divinization through grace, and the divinity of Christ himself is just that our divinity is a gift from the Father through Christ, the gift we call the Holy Spirit. This is the precise meaning of the statement that it is grace that makes us free. This does not mean that without grace we are incapable of free decisions; it means that without grace we are stuck in a servant/master relationship to God (and an unfaithful servant at that) instead of participating in the divine life itself. Our freedom in this sense is precisely the “glorious freedom of the children of God”—where “children” is contrasted not with adults but with “servants of the household.” Without this divine life we are, as Paul puts it, “under the law”—he means the moral law of God. Without this divine life we would have to live according to rules laid down by our master, our creator. Excellent rules, of course; none other than the way of life that would lead to human flourishing and fulfilment and happiness, liberated from idolatry and all the gods, but nonetheless rules laid down by our master and maker. To live ultimately under law in this sense, even a good law, is in the end to be a slave. There is of course nothing wrong with laws; they are a necessary part of social life. But to be obedient to a law is not, for the gospel, the essence of man, the deepest thing about him. The essence of man is freedom. It is a mysterious fact about human beings that even to conform to the law of our own being is to be restricted. We naturally tend beyond ourselves.
Fr Herbert McCabe, O.P.