Reply to Objection 1: To be wise or intelligent is taken only essentially in God; therefore we cannot say that "the Father is wise or intelligent by the Son." But to love is taken not only essentially, but also in a notional sense; and in this way, we can say that the Father and the Son love each other by the Holy Ghost, as was above explained.
Reply to Objection 2: When the idea of an action includes a determined effect, the principle of the action may be denominated both from the action, and from the effect; so we can say, for instance, that a tree flowers by its flowering and by its flower. When, however, the idea of an action does not include a determined effect, then in that case, the principle of the action cannot be denominated from the effect, but only from the action. For we do not say that the tree produces the flower by the flower, but by the production of the flower. So when we say, "spirates" or "begets," this imports only a notional act. Hence we cannot say that the Father spirates by the Holy Ghost, or begets by the Son. But we can say that the Father speaks by the Word, as by the Person proceeding, "and speaks by the speaking," as by a notional act; forasmuch as "to speak" imports a determinate person proceeding; since "to speak" means to produce a word. Likewise to love, taken in a notional sense, means to produce love; and so it can be said that the Father loves the Son by the Holy Ghost, as by the person proceeding, and by Love itself as a notional act.
Reply to Objection 3: The Father loves not only the Son, but also Himself and us, by the Holy Ghost; because, as above explained, to love, taken in a notional sense, not only imports the production of a divine person, but also the person produced, by way of love, which has relation to the object loved. Hence, as the Father speaks Himself and every creature by His begotten Word, inasmuch as the Word "begotten" adequately represents the Father and every creature; so He loves Himself and every creature by the Holy Ghost, inasmuch as the Holy Ghost proceeds as the love of the primal goodness whereby the Father loves Himself and every creature. Thus it is evident that relation to the creature is implied both in the Word and in the proceeding Love, as it were in a secondary way, inasmuch as the divine truth and goodness are a principle of understanding and loving all creatures.