Proslogium and Monologium/Monologium/Chapter42

Chapter XLII
It is the property of the one to be most truly progenitor and Father, and of the other to be the begotten and Son.

I should certainly be glad, and perhaps able, now to reach the conclusion, that he is most truly the Father, while this Word is most truly his Son. But I think that even this question should not be neglected: whether it is more fitting to call them Father and Son, than mother and daughter, since in them there is no distinction of sex.

For, if it is consistent with the nature of the one to be the Father, and of his offspring to be the Son, because both are Spirit (Spiritus, masculine); why is it not, with equal reason, consistent with the nature of the one to be the mother, and the other the daughter, since both are truth and wisdom (veritas et sapientia, feminine)?

Or, is it because in these natures that have a difference of sex, it belongs to the superior sex to be father or son, and to the inferior to be mother or daughter? And this is certainly a natural fact in most instances, but in some the contrary is true, as among certain kinds of birds, among which the female is always larger and stronger, while the male is smaller and weaker.

At any rate, it is more consistent to call the supreme Spirit father than mother, for this reason, that the first and principal cause of offspring is always in the father. For, if the maternal cause is ever in some way preceded by the paternal, it is exceedingly inconsistent that the name mother should be attached to that parent with which, for the generation of offspring, no other cause is associated, and which no other precedes. It is, therefore, most true that the supreme Spirit is Father of his offspring. But, if the son is always more like the father than is the daughter, while nothing is more like the supreme Father than his offspring; then it is most true that this offspring is not a daughter, but a Son.

Hence, just as it is the property of the one most truly to beget, and of the other to be begotten, so it is the property of the one to be most truly progenitor, and of the other to be most truly begotten. And as the one is most truly the parent, and the other his offspring, so the one is most truly Father, and the other most truly Son.