Hilary of Poitiers

(vii. de Trin. c. 27, 28) Living born from living, hath the perfection of nativity, without the newness of nature. For there is nothing new implied in generation from living to living, the life not coming at its birth from nothing. And the life which derives its birth from life, must by the unity of nature, and the sacrament of a perfect birth, both be in the living being, and have the being who lives it, in itself. Weak human nature indeed is made up of unequal elements, and brought to life out of inanimate matter; nor does the human offspring live for some time after it is begotten. Neither does it wholly live from life, since much grows up in it insensibly, and decays insensibly. But in the case of God, the whole of what He is, lives: for God is life, and from life, can nothing be but what is living.