We can perceive from this discussion the nature of the order between the personal acts and the personal properties. The personal properties are subsistent persons. But a person subsisting in any nature whatsoever, acts in virtue of his nature when he communicates his nature; for the form of a species is the principle for generating a product that is of like species. Consequently, since personal acts in God have to do with communicating the divine nature, a subsisting person must communicate the common nature in virtue of the nature itself.
Two conclusions follow from this. The first is, that the generative power of the Father is the divine nature itself; for the power of performing any action is the principle in virtue of which a thing acts. The second conclusion is that, according to our way of conceiving, the personal act of generation presupposes both the divine nature and the personal property of the Father, which is the very hypostasis of the Father. This is true even though such property, regarded as a relation, follows from the act. Thus, in speaking of the Father, if we attend to the fact that He is a subsistent person, we can say that He generates because He is the Father. But if we are thinking of what pertains to relationship, it seems we should say, contrariwise, that He is the Father because He generates.
St. Thomas Aquinas. (1265-1274). Compendium Theologiae: Personal Acts and Personal Properties, trans. by Cyril Vollert. St. Louis & London: B. Herder Book Co., 1947
All scripture is given by inspiration of God and is profitable for doctrine, reproof, correction, and instruction in righteousness (2 Timothy 3:16).