“If Creation is the act by which the whole of one’s being is constituted, then the creature is nothing but a relationship to God. In light of Thomas’s understanding of creation, relation, not substance, is the primary category of reality. It is not as though God makes things with which he then establishes a relationship; on the contrary, from the beginning, all ‘things’ already are relations to the divine source. We are most ourselves precisely when we acknowledge that what we are, most fundamentally, is a rapport, a play, a dynamic relation to God.”
Blogger: To say there is substance as, or in, the natural, created order is to be an atheist unawares. It is to be trapped in the mindset (epistemology) of the Greek pagan world, or the Modern Theism of the Enlightenment. To sense reality as created and "substance" (and by "substance" I understand being-in-itself), is to understand the Creator as substance (Being-in itself). And so, we end up with the Creator-God in the same category of Being as His creation, only He is "Supreme Being."We have parallel realities in the same mental category of "Being." But this is not the Judeo-Christian God. He is an "object" of thought rather "greater than which nothing can be thought" (Anselm). What I am writing here is merely an exercise in Sokolowski's phenomenology (which is the way of thinking of the early Fathers of the Church). That is, God alone really is; nothing else really is. And this is thomistic metaphysics: the Creating God is Ipsum Esse Subsistens. Everything else is habens esse.
The question is, can we take the following seriously: "In the beginning was the Word, and the Word was with God; and the Word was God. He was in the beginning with God. All things were made through him, and without him was made nothing that has been made" (Jn. 1, 1-3)? If this is true, then the Aristotelian "substance" as the prius of what is real has been misplaced, and as Paul Tillich said of St. Thomas in this regard, such a misplacement has been the cause of the progressive secularism of the West. That is, somehow, the world and God are parallel realities with the only difference being that God is the Most and Supreme. They are in the same category of Being - which means that God is part of the world although the supreme part; and it would implicitly deny that God is Creator of the world - as well as deny that He creates ex nihilo, from nothing.
We have all been brought up on the 5 Ways of St. Thomas from the Summa Theologiae and Contra Gentiles that basically becomes so-called "Natural Theology” in later Scholasticism:" God is first Cause, Prime Mover, Necessary Being, Perfect Being and Final End; and all perfections in God are deduced from His simplicity of being Pure Act. Of course, this also applies to Aristotle's Prote Ousia, which is not Creator.
The rub for Barron came from reading Paul Tillich (Lutheran Theologian) [as a way, he told us (myself and two other priests), of improving his German].
"What one finds, in short, is that Tillich’s reading of Thomas as a cosmological theologian, as a proponent of an ens summum notion of God, breaks down around this Urfrage of creation. An interpretation of Thomas, which is shared even by many Catholic thinkers sympathetic to the Angelic Doctor, cannot stand in light of Aquinas’ own doctrine of creatio ex nihilo. This conflict, this tension, between Tillich’s critique and Thomas’ surprising doctrine, led me to suspect that there might be something unexpected at work chez Aquinas. In more positive terms, the similarity between Tillich and Thomas on the central issue of creation led me to wonder whether the Angelic Doctor himself might be far mor ‘ontological than ‘cosmological,’ far more oriented to revelation than to ‘natural theology, far more Christological than metaphysical. Indeed, if God is not a being in or alongside of the world, but the unconditioned act of being itself, would it not follow necessarily that, for Thomas himself, rational ‘proofs’ could never attain God. Would it not be the case that such a God could only be given in an overwhelming act of self-disclosure, in what Tillich calls revelation? Would not such a God appear, Tillich argues, in the immediate certitude prior to the split between subject and object? In a word, I wondered whether Thomas’ creation teaching, in its radicality, might prompt a re-thinking, a re-evaluation of the working of the thomistic system as a whole.
Inspired by this ‘Tillichean’ Thomas of creation, I turned to the great texts of the mature Aquinas on revelation and the starting-point of theological reflection. What I found is that the ‘cosmological’ Thomas disappears.”
Blogger: And what appears? The Christological Thomas! And so Barron discovers a Christologically centered Aquinas, and therefore finds the relation between the Creator and creation not through cosmological perception but within the Person of Christ as the center, cause and purpose of the material universe. And this then means that the relation between the divine nature and the human nature obtain in the single Person. This then shifts the investigation of Creator and creation to the Christology which the Church offered in the Third Council of Constantinople (680-681), and which has been popularized by Joseph Ratzinger in the retreat he preached to John Paul II in Lent of 1983. There Ratzinger clarified that the divine and the human natures – read uncreated and created – are not in parallel but “compenetrated,” meaning that they are two conduits of the same divine Self. This needs to be clarified in that the divine will and the human will do not will in some kind of resonance as wills. Rather, it must be philosophically clarified that wills do not will. Only persons (subjects) will. That it is the same Person who is willing as God and as man; and yet they are ontologically distinct in that one is uncreated, the other created. And, since it is a Person tending through the wills, the willing of both will be the giving of the divine Self. Ratzinger invents the neologism “compenetrated” to explain how they are one will, yet ontologically distinct. The failure to understand this has left us with the unresolved dualisms of for example, faith-reason, grace-nature, church-state. We can’t solve these dualisms because we are thinking that they are “out there” when they are resolved only within a lived Christ (and this for everybody, Christian or otherwise, church affiliated or not. It’s anthropological).
So, what does Bishop Robert Barron say?
“Thomas saw in the event of the Incarnation the strangeness of both God and creature and was thus led to a radical re - imagination of the real. [Blogger: I take this last sentence as of major importance: to radically re-imagine the real. That is, we don’t see sensible, material reality as it really is, and this because we have been damaged by sin. Our perception has been distorted because of the turn to the self and the loss of the experience and therefore meaning of sensible things]. And this, again, because we fail to experience the self going out of self in the very exercise of sensible perception, and we perceive through sight, touch, taste and feel for ourselves. Therefore, since like is known by like, we don’t see sensible reality as subjectively related to the “I” of the Creator as receptivity, but rather as “thing-in-itself” (substance)]. What Aristotle saw as a realm of substances in accidental relation to a prime mover, a supreme and self-absorbed substance, Thomas saw as an arena of creatures, that is to say, sheer relations to an immanent/transcendent act of self-emptying love. Did the coming-together of the natures of Christ - personal union yet without mingling or confusion –signal to him that something else might be the case with regard to both the divine and the non - divine? And, if I might speculate a bit further, did he see that the world articulated by Aristotle and corresponding to a common-sense view of things, is the illusory world prodouced by sin?[my emphasis]Is itghe blocky universe of omutually exclusive divine and nondivine substances not the universe overcome in the revelationofthe Inarnation? And does Thomas not give us – in his theological undermining of both the supreme being and supreme ego- a glimpse of a new world?”
 Robert Barron “Thomas Aquinas - Spiritual Master” Crossroad (2000) 120.
 Barron is at pains consistently to point out that the error here begins with Scotus and Occam which devolves into a decayed and rationalist scholasticism – a univocity of beinjg as category, and leads to the Cogito and the Watchmaker-Creator of the Enlightenment – a throwback to the Greek Prime Mover as part of the world.
 There is no possibility of Scotus’ and Occam’s univocity of being in the Creatio ex nihilo.
 General Intro to “A Study of the De Potentia of Thomas Aquinas in Light of the Dogmatik of Paul Tillich” 11-12.
 “We are reminded firmly that there exists a specific will of the man Jesus that is not absorbed into the divine will. But this human will follows the divine will and thus becomes a single will with it, not, however, in a forced way but by way of freedom. The metaphysical duplicity of a human will and a divine will is not eliminated, but in the personal sphere, the area of freedom, there is accomplished a fusion of the two, so that this becomes not one single natural will but one personal will;” Benedict XVI “Journey to Easter,” Crossroad (1987) 100-101.
Consider the remarks of Pope Francis in “Laudato Si” #233: “The universe unfolds in God, who fills it completely. Hence, there is a mystical meaning to be found in a leaf, in a mountain trail, in a dew drop, in a poor person’s face. The ideal is not only to pass from the exterior to the interior to discover the action of God in the soul, but also to discover God in all things.” And in footnote #159. “There is a subtle mystery in each of the movements and sounds of this world. The initiate will capture what is being said when the wind blows, the trees sway, water flows, flies buzz, doors creak, birds sing, or in the sound of stings of flutes, the sighs of the sick, the groans of the afflicted…”
 R. Barron, “Thomas Aquinas’ Christological Reading of God and the Creature,” Bridging the Great Divide, Rowman and Litt lefield, (2004) 104.