Right now as I write, and right now as you read, everything in the universe continues to exist because Christ is maintaining it. It is he, says the writer of Hebrews, who "upholds the universe by the word of his power" (Hebrews 1:3). Paul says something similar in Colossians 1:17: It is in Christ that "all things hold together." The laws of the universe are laws because Christ upholds them. He sustains the gravity that sticks everything together.
Christ and his creation are not like a watchmaker and his watch. A watchmaker assembles a watch, winds it up, and lets it run. There is no “letting it run” with Christ; He keeps the universe moving along by his own power. What’s here is here because he made it, and it keeps on working because he continues to make it work.
But the difference between Christ and the watchmaker is even greater than this. Leon Morris says the thought in Hebrews 1:3 is that Christ
is carrying [the universe] along, bearing it toward an important goal. Creation is not aimless; it is part of God's plan and the Son is continually bearing creation along toward the fulfillment of the plan.1A watchmaker winds his watch and lets it run until it winds down. The watch fulfills its purpose best at the very beginning if its existence when it is new and freshly wound. Someday, inevitably, it will wind down and stop forever, never to fulfill its true purpose again. Not so with creation. Creation is forever fulfilling it's purpose perfectly because it is being moved toward its ultimate aim by the One who made it.
The winding down we see in creation—everything and everyone dies, for instance, and the weeds in my garden grow faster than I can pull them—is purposeful winding down. It's a winding down that's moving forward. The creation, Paul says in Romans 8:20, "was subjected to futility . . . in hope." Hope, biblically speaking, isn't a wonderful future that might or might not happen, but a wonderful future that is rock solid certain. In its futility—or in its winding down, to use the watch analogy—creation is moving toward a day when it will be made new. It will be recreated into something better than it was on the day before the first humans ate the forbidden fruit and the winding down began.
What goes for creation, goes for believers, too.2 My aging and aching body, marching relentlessly toward death, is, in the same forward motion, being carried toward resurrection.
And the whole shebang—all of creation and all of us—is being transported into the golden future by Christ’s powerful word. Later, in Hebrews 11:3, the writer tells us that the universe was created by God's word; here, it's Christ's word that bears universe toward God’s goal for it. This is a perfect time to use the word fiat—a command that, by itself, creates or accomplishes what it commands. Christ created by fiat and he upholds by fiat. Christ commands and the universe responds, first by coming into existence, and then by moving forward toward a perfect destiny.
I consider the words in the title to this post to be some of the most intriguing in scripture. God’s powerful word, which is able to bring things into existence out of nothing, was not spoken once in the past at creation, but is spoken for every nanosecond of time and every nanosecond of my life. There is an eternal and personal will keeping the universe and my life together, and an eternal and personal energy source carrying them along. Christ’s command calls up the sprouting seeds in my garden, his command pulls down the crumpled leaves on my Mayday tree, and his command moves my life forward toward death, but also into what will be, in the end, a glorious resurrection. What seems like futility is Christ's powerful word bringing it all—and me, too—toward a perfect fulfillment.
1 Leon Morris, Hebrews: Bible Study Commentary, page 20.
2 Although scripturally, it's more accurate to put priority on us and say that what goes for believers goes for the rest of creation. We bring creation with us into its future freedom from the effects of sin.