He holds all things in existence

Aristotle said that “whatever is greatest in being and greatest in truth, is the cause of every being and of every truth,” just as “whatever is the greatest in heat is the cause of all heat.”

St. Thomas Aquinas, Summa Theologica I., Q. 44, A. 1.

He shewed me a little thing, the quantity of an hazel-nut, in the palm of my hand; and it was as round as a ball. I looked thereupon with eye of my understanding, and thought: What may this be? And it was answered generally thus: It is all that is made. I marvelled how it might last, for methought it might suddenly have fallen to naught for little. And I was answered in my understanding: It lasteth, and ever shall for that God loveth it. And so All-thing hath the Being by the love of God.

Julian of Norwich, Revelations of Divine Love (c.1393), Chapter 5.

Who committed the earth to his keeping?
Who but he established the whole world?

If he were to turn his thoughts inwards
and withdraw his life-giving spirit,
all flesh would perish on the instant,
all mortals would turn again to dust.

Job 34:13-15.