Works of St. Anselm, tr. by Sidney Norton Deane, [1903], at sacred-texts.com
SINCE this love, then, has its being equally from Father and Son, and is so like both that it is in no wise unlike them, but is altogether identical with them; is it to be regarded as their Son or offspring? But, as the Word, so soon as it is examined, declares itself to be the offspring of him from whom it derives existence, by displaying a manifold likeness to its parent; so love plainly denies that it sustains such a relation, since, so long as it is conceived to proceed from Father and Son, it does not at once show to one who contemplates it so evident a likeness to him from whom it derives existence, although deliberate reasoning teaches us that it is altogether identical with Father and Son.
Therefore, if it is their offspring, either one of them is its father and the other its mother, or each is its father, or mother, ‑‑ suppositions which apparently contradict all truth. For, since it proceeds in precisely the same way from the Father as from the Son, regard for truth does not allow the relations of Father and Son to it to be described by different words; therefore, the one is not its father, the other its mother. But that there are two beings which, taken separately, bear each the perfect relation of father or mother, differing in no respect, to some one being ‑‑of this no existing nature allows proof by any example.
Hence, both, that is, Father and Son, are not father and mother of the love emanating from them. It p. 116 therefore is apparently most inconsistent with truth that their identical love should be their son or offspring.