Divine aseity as a doctrine and reality has helped me almost more than any other theological locus I can think of. That might seem strange given my apparent predisposition towards kataphatic theology, or theology based solely on God’s Self-revelation in Jesus Christ. But it is this white-hot purifying reality that seemingly God himself has brought me back to over and over again. When the Lord really got a depth hold on me say back in 1995ish (moving me beyond my childhood faith—which was real), he used reality and existence as his means. I became hyper aware, even fixated upon reality and unreality, to the point that it caused me anxiety of the sort I would rather never repeat again. But the reality is is that he learned me into his reality, the reality that all other perceived and physically observable reality pales compared to his real reality. It is the childish idea of getting fixated on the thought that God always just has existed; with no external cause or source, he just is. I say childish because this idea operates under the assumption that God is of a sort—qualitatively—that fits into the created class; as if if we could burrow deep enough we’d finally come to some sort of ‘beginning’ for God. This is childish; we ought to move into meatier ideas about God. Aseity offers a meaty way to think God, but not comprehend him nor circumscribe him with our own powers; aseity simply identifies a reality about God—from his gracious Self-revelation—that recognizes our inability to surmise such a being. This is a purifying reality.
In order to gain better traction on what Divine aseity entails let’s hear from a theologian who I would call a theologian of Divine aseity, the late John Webster. In the following he describes and defines for us the entailments of God’s aseity. I’ll follow with some further reflection based upon Webster’s insights:
Second, it indicates that God’s originality and fullness constitute the ground of his self-communication. He is the one who, out of nothing other than his own self-sufficiency, brings creatures into being, sustains and reconciles them, and brings them to perfection in fellowship with himself. A theology of God’s aseity is an indication of the one who is and acts thus, who is the object of the church’s knowledge, love and fear, and whose praise is the church’s chief employment.
The concept of aseity tries to indicate God’s identity; it is not a definition of God but a gesture towards God’s objective and self-expressive being. The task of the concept is not to establish conditions for conceivability but rather to have rational dealings with the God who is, and is self-communicative, anterior to rational work on our part. God is objective and expressive being, presenting himself to us and making himself perceptible, intelligible and nameable (this is part of the meaning of ‘revelation’). Consequently, in theology aseity is a positive or material concept, determined by the particular form of God’s self-expressive perfection. Its content is grasped as regenerate intelligence, prompted by divine instruction, considers God absolutely and relatively, in his inner being and his outer works. Because of this, theology will not over-invest in whatever generic sense may be attached to the concept of aseity (or of any of the other divine attributes). This, not because of intellectual sectarianism, a desire to segregate theological use in an absolute way from all other speech about deity – after all, aseity, like nearly all Christian theological concepts, is a borrowed term with a wider currency. Rather, theology is simply concerned to ensure that its talk of aseity concentrates on that which is proper to this one.
Do you see how as a limiting doctrine, insofar as it recognizes the type of capacities we have as creatures to think God, this might have a purifying impact? It places the Christian supplicant up against the mighty reality of God. Personally as I ponder this reality the created order gains a proper order; maybe not in a fully spelled out sense, but in the sense that the whole world, as Isaiah notes, is nothing more than a ‘drop in a bucket’ before God. Living in the reality of God’s aseity takes the pressure off of me to perform and sustain, and places that burden on the shoulders it should be placed. Aseity recognizes that God is God and I am not, and it’s a relief. Aseity contradicts the original lie of Genesis 3; a lie that has placed untold burden on humanity, a burden that makes it seem like each individual human being must assert its own inner-divinity. Aseity takes that away from the creature and recognizes that God alone is big enough to bear the burdens of holding the world together; even our own worlds that seemingly fall apart the moment we wake up each day.
For the Christian aseity does not suggest a nebulous reality greater than can be conceived; instead aseity is particularized in the God-man for us, Jesus Christ (thinking about how the Deus absconditus is Deus revelatus – the ‘hidden God’ is the ‘revealed God’). In other words, aseity, for the Christian comes to us in personal terms. The Son introduces us to the Father by the Holy Spirit and we enter into his reality by grace becoming participants and partakers of the divine nature wherein recognition of just who this God, our God is. He truly is. It is this personal reality that makes thinking aseity possible; in other words, God’s Self-revelation sets the conditions for coming to recognition that God just is. Just is in the sense that he just is without explanation; he’s just there, and he’s said he’s just there for us—and he said this in such a way that his self-sufficiency in his inexplicability is the basis upon which he has freely chosen to be for us apart from needing us to be who he is for and with us.
An aside. Like I noted above, I struggled with serious anxiety and depression for many years; much of that had to do with precisely this issue: the issue of reality and existence. When we can start to live and move in the reality of God’s aseity, in the face of Jesus Christ, so many of the pressures we place upon ourselves simply melt away. I would suggest that much of what our culture popularly and even academically identifies as mental-illness in the 21st century context is a result of the human condition and its inner-impulse and propulsion to be God without having the a se resource to actually pull such a feat off. Coming to the brink of my own beginning and end by living in the recognition that God, who has no beginning or end, becomes the strong shelter, the everlasting arms I constantly flee to to find refuge. When I can come to that place, as the prophets speak of, that I am just silent before this God who just is, it is here that the shalom of God comes to be experienced. I am not suggesting that mental and other issues are magically ‘cured’ by coming to live in the realization of God’s a se life, but I am suggesting that without this recognition the conditions for personal liberation and healing (in a genuinely theological proper way) will not be present.
 John Webster, God Without Measure: Working Papers In Christian Theology: Volume 1 God And The Works Of God (London-New York: Bloomsbury T&T Clark, 2015), Loc 283, 290, 296 kindle version.