“Even youths shall faint and be weary, and young men shall fall exhausted; but they who wait for the LORD shall renew their strength; they shall mount up with wings like eagles; they shall run and not be weary; they shall walk and not faint” (Isa. 40:30–31).

Before kids, Adrienne and I used to go on a lot of boondoggle adventures. Once, we drove to Monument Valley to watch a movie shot there called The Searchers. It was a great trip, but our gas tank kept running lower and lower on the way there. We didn’t realize we’d have to drive through the Navajo Nation reservation for so long without service stations or cell coverage. At some point, you move from watching for the next station to praying for help. It felt like we drove with that tank on “E” forever, but eventually, we found relief from our stress and fueled up our tank.

Maybe you’ve felt yourself running on empty at times, worn down by the seemingly endless chain of hard days and anxious nights. We’ll all eventually sputter if we run only on our resources.

Isaiah 40 encourages powerless people to renew their strength. But there’s a condition for renewal. Only “those who wait on the Lord” will “renew their strength” (Isa. 40:31). Far from running on empty, they will “run and not be weary” (Isa. 40:31) filled up by Yahweh.

We’ll all eventually sputter if we run only on our resources.

Faint and weary are two keywords used seven times in these four verses (Isa. 40:27-31). Motyer explains that the Hebrew word for “faint” means “failure through loss of inherent strength.” “Weary” refers to “exhaustion because of the hardness of life.” The Lord leads us from “exhausted” — tottering near collapse from fatigue — to renewal with an unflagging divine power that gives us wings.

A Time of Trouble

Before we apply this promise to ourselves, let’s consider the historical and literary context of Isaiah 40. The previous chapter foretold when Judah’s wealth and princes would be “carried to Babylon” (Isa. 39:6-7). The second half of the book (Isa. 40-66) speaks to those exiled in Babylon 150 years after Isaiah’s time (Isa. 48:20). The prophet wants to help them sustain their faith as they wrestle with the horrors they’ve seen, the promises they now question, and the loss of temple, land, and king. Their concerns won’t resolve for some time, yet like Jeremiah, who lived through it all (Lam. 3:19-27), he urges the most defiant, courageous act imaginable: confidently waiting on God (Isa. 40:30). 

Judah wonders if God even notices their situation, considering he let their whole world fall apart (Isa. 40:27). Why would he allow this? They might conclude either he doesn’t care or he can’t help. But Isaiah assures them God does care (Isa. 40:1-11). He wants to comfort and pardon them (Isa. 40:1-2). Yahweh will come to save (Isa. 40:3-5), so they should trust his promises (Isa. 40:6-8) because their mighty shepherd will carry his flock (Isa. 40:9-11). And he’s able to save (Isa. 40:12-26). He has power over the universe (Isa. 40:12-20) and history (Isa. 40:21-24).

The One Limitless Power Source

On December 5, 2022, scientists at California’s National Ignition Facility reportedly produced more power from a nuclear fusion reaction than they put in. Forbes reported that “researchers believe we’re within four decades of producing 100% clean, limitless energy,” calling this a “century-long quest to unlock the power of the sun on earth.” It reminds me of Superman harnessing our sun’s power into invincible strength. But just like our cars and phones, even our sun will eventually run out of energy. 

You have limits, but your God is limitless in understanding and might.

Everything in this world “faints” and needs renewal, including you. You may think you just need to keep powering through, but you’re not Superman. You have limits, but your God is limitless in understanding and might. He is “the everlasting God, the Creator of the ends of the earth” who “does not faint or grow weary” (Isa. 40:28).

The “youths” in the prime of their lives and even “young men” trained and chosen for “bodily prowess” (Motyer) will fall over depleted (Isa. 40:30). Elite athletes like the world’s “fastest man” fall victim to human frailty, as we saw at the Olympics when Noah Lyles couldn’t compete in his best event due to COVID, days after winning gold in the 100 meter. But “they who wait for the Lord shall renew their strength; they shall mount up with wings like eagles; they shall run and not be weary; they shall walk and not faint” (Isa. 40:31). 

Trouble is time-bound, separated from God’s answer by time. Holding onto faith across that time is waiting on the Lord.

Learning How to Wait

Isaiah prayed, “O Lord, be gracious to us; we wait for you. Be our arm every morning, our salvation in the time of trouble“ (Isa. 33:2). When do we wait? In a TIME of “trouble.” Trouble is time-bound, separated from God’s answer by time. Holding onto faith across that time is “waiting on the Lord.”

John Oswalt called it “complete dependence on God and a willingness to allow him to decide the terms … not merely killing time but a life of confident expectation. Those who give up their own frantic efforts to save themselves and turn expectantly to God will be able to replace or exchange (yaḥalîpû) their worn-out strength for new strength.” It doesn’t necessarily mean doing nothing, because it includes everything faith includes — allegiance and confidence, acting in obedience and yielding in stillness and when an issue belongs to God.

The condition God gives for soaring beyond weariness is to hold onto him in hope. It doesn’t require a particular answer to our prayers. It’s a strength beyond circumstance. When we wait on him, we will be “renewed day by day” (2 Cor. 4:16).