Lugwig Ott’s book says it’s de fide that “The Divine Persons, not the Divine Nature, are the subject of the Internal Divine processions .” Yet the Church teaches “The Relations in God are really identical with the Divine Nature.” (Ott). So how can the Father’s reason be prior to the Son, since “Fatherhood’s reason” begets him? This is what let me to consider that the will is prior to the divine goodness, as well being a mystery. Thus Jesus says that men are not good but only God
It is due to absolute simplicity of God. The real difference in persons is not one of composition, and is by our thinking.
That *de fide *dogma is from the Fourth Lateran Council (1215):
“(The Divine Substance) does not generate nor is it generated nor does it proceed; It is the Father who generatest the Son who is generated and the Holy Ghost who proceeds.”
The second de fide dogma you mention is from Council of Florence:
“In God everything is one except there be an opposition of relation”.
The Catechism includes this and the dogma of the circumincession:
255 The divine persons are relative to one another. Because it does not divide the divine unity, the real distinction of the persons from one another resides solely in the relationships which relate them to one another: "In the relational names of the persons the Father is related to the Son, the Son to the Father, and the Holy Spirit to both. While they are called three persons in view of their relations, we believe in one nature or substance."89 Indeed "everything (in them) is one where there is no opposition of relationship."90 "Because of that unity the Father is wholly in the Son and wholly in the Holy Spirit; the Son is wholly in the Father and wholly in the Holy Spirit; the Holy Spirit is wholly in the Father and wholly in the Son."91.
Fundamentals of Catholic Dogma (Ludwig Ott) also includes that “Between the Divine Relations and the Divine Nature however, no relative opposition exists”.
So, with that background, see what St. Thomas Aquinas states in Summa Theologica Q39 A1, that essence is not really distinct from person:
I answer that, The truth of this question is quite clear if we consider the divine simplicity. For it was shown above (Question 3, Article 3) that the divine simplicity requires that in God essence is the same as “suppositum,” which in intellectual substances is nothing else than person. But a difficulty seems to arise from the fact that while the divine persons are multiplied, the essence nevertheless retains its unity. And because, as Boethius says (De Trin. i), “relation multiplies the Trinity of persons,” some have thought that in God essence and person differ, forasmuch as they held the relations to be “adjacent”; considering only in the relations the idea of “reference to another,” and not the relations as realities. But as it was shown above (Question 28, Article 2) in creatures relations are accidental, whereas in God they are the divine essence itself. Thence it follows that in God essence is not really distinct from person; and yet that the persons are really distinguished from each other. For person, as above stated (29, 4), signifies relation as subsisting in the divine nature. But relation as referred to the essence does not differ therefrom really, but only in our way of thinking; while as referred to an opposite relation, it has a real distinction by virtue of that opposition. Thus there are one essence and three persons.
Reply to Objection 2. As essence and person in God differ in our way of thinking, it follows that something can be denied of the one and affirmed of the other; and therefore, when we suppose the one, we need not suppose the other.
In Summa Theologica, Q41 A5 the other part is explained:
Objection 2: Further, in God, the power to act [posse] and ‘to act’ are not distinct. But in God, begetting signifies relation. Therefore, the same applies to the power of begetting.
Reply to Objection 2: As in God, the power of begetting is the same as the act of begetting, so the divine essence is the same in reality as the act of begetting or paternity; although there is a distinction of reason.