In human generation, the human nature is divisible. It can, Francis Turretin says, “remain the same in species when propagated by generation, although it is not the same in number because it detaches a certain part of its substance, which passes over to the begotten.” That’s because human generation is physical and material. The divine nature, however, is spiritual and therefore indivisible. God is spirit, so He remains one, simple, and undivided. Thus, some call the generation of the Son hyperphysical to communicate that the Son’s generation is not in time or space; nor does it result in divisible parts.
As mentioned, the Son does not receive what the Father received from His father, since the Father has no father Himself. It does not follow, however, that the Son is born out of nothing (ex nihilo) as the Arians insisted. If He was, then He would be no different from the rest of creation, which was made by God out of nothing. But the Son is no creature; yes, He is begotten, but He is not made (Nicaea). Let’s not confuse the two. Rather than the Son being “born out of nothing,” Thomas Aquinas says, He is “born out of the substance of the Father.”
Again, this should not be taken in the human sense. The “Son of God is born of the substance of the Father. Yet not in the same way as a human son. For a part of the substance of the human father passes into the substance of his offspring.” That would divide up the substance or nature of God. By contrast, the divine substance “is above being divisible.” The Father “in begetting the Son did not pass on part of his nature to the Son, but bestowed the whole nature upon him, with only the distinction based on origin remaining.” The divine nature belongs to the Son—not in part, but in whole—due to His origin from the Father, and if in whole then the divine nature has been neither multiplied nor divided.
Notice, divine simplicity plays a major factor at this point. Since God is not made up of parts, it’s not as if eternal generation involves a portion of the divine essence being broken off and given to the Son by the Father. The Son, Hilary of Poitiers objects, is no “mutilated fragment of the Father.” Not only would that make God a composition of parts, but it would sacrifice the full deity of the Son, as if He were only part divinity. Nor would the Trinity be simply Trinity. Rather, to be begotten from the Father is to wholly possess the one, undivided divine essence. “That birth, which brought Him into being, constituted Him divine, and His being reveals the consciousness of that divine nature. God the Son confesses God His Father, because He was born of Him; but also, because He was born, He inherits the whole nature of God.” Each person is a subsistence of the one divine nature, that nature wholly subsisting in Father, Son, and Holy Spirit. “The Son is begotten of (de) the Father’s essence,” Thomas Aquinas says, “because the Father’s essence, bestowed on the Son through generation, is subsisting in the Son.”
Since the Son is begotten of the Father’s essence, there is “no partition, or withdrawing, or lessening, or efflux, or extension, or suffering of change, but the birth of living nature from living nature”; eternal generation is “One from One,” that is, “God going forth from God.” Or as the Nicene Creed says, the Son is “true God from true God.” The Son’s existence “did not take its beginning out of nothing, but went forth from the Eternal.” It is appropriate to still call it a birth (that is the meaning of begetting), but “it would be false to call it a beginning.” Birth, not beginning. Unlike the creation of the universe ex nihilo, the “proceeding forth of God from God is a thing entirely different from the coming into existence of a new substance.” Hilary is right: the Son “has no origin external to God, and was not created out of nothing, but is the Son, born from God.”
If the Son’s generation involves no multiplication or division, are we safe to conclude that it can involve no priority and mutation either? The answer to that question will launch our final adventure in the next article, and it may just be the most important adventure yet.
Editor’s Note: This post is part of a series on the Trinity. Previous post. Next post.