The Instructor 1.6.49

From all this it is plain that blood is the substance of the human body. Indeed, what is in the womb is at first a milk-like consistency of liquid; then this consistency becomes blood and turns into flesh; and, set in the womb by the natural and warm breath by which the embryo is shaped, it is brought to life. And after birth the child is nourished again by the same blood; for the flow of milk is of the nature of blood, and milk is the spring of nourishment, by which a woman is shown to have truly given birth and to be a mother, and by which she gains a charm of love. That is why, mystically, the Holy Spirit in the apostle, using the voice of the Lord, says, “I gave you milk to drink.” For if we have been born again into Christ, he who regenerated us nourishes us with his own milk, the Word; for everything that begets seems at once to supply food to what is begotten. And as the new birth is spiritual, so correspondingly the food of the human being has become spiritual. In every way, then, we have been united to Christ in all things: into kinship through his blood, by which we are redeemed; into sympathy through the nurture that comes from the Word; and into incorruption through his training. “Among mortals, rearing children often wins more love than begetting them.”