They shall mount up with wings as eagles
28 Hast thou not known? hast thou not heard, that the everlasting God, the LORD, the Creator of the ends of the earth, fainteth not, neither is weary? there is no searching of his understanding. 29 He giveth power to the faint; and to them that have no might he increaseth strength. 30 Even the youths shall faint and be weary, and the young men shall utterly fall: 31 But they that wait upon the LORD shall renew their strength; they shall mount up with wings as eagles; they shall run, and not be weary; and they shall walk, and not faint. (Isaiah 40:28-31)
Chariots of Fire shows us two ways that “young men” can run. Harold Abrahams is every inch the driven man. At one point he explains why he must win gold at the 100 metres: “I have 10 seconds to justify my existence.” That’s one way to run.
On the other hand, Eric Liddell is a man who knows how to wait on the LORD. He even forgoes Olympic glory to rest on a Sunday. Does this mean he has forgotten about running? No. It’s just that he runs for a very different reason: “When I run I feel His pleasure.”
One man runs to prove himself. The other abandons himself to the LORD and now he can simply enjoy the running. Two ways to run – two ways to live. Either we do it in our own strength, to justify our own existence. Or, in dependence on the LORD’s strength, we entrust our justification and life to Him. When we do that we receive it back as renewed strength.
When verse 31 says the LORD shall “renew” their strength, it’s a word that most often means to “change” or “exchange”. It’s a swap which the LORD offers.
He receives our weakness to Himself. In that ultimate sense, He takes on our frailty, becoming flesh and running our race all the way to its bitter end at the cross (Hebrews 12:1-3). But He rises again by the power of the Spirit and offers us a cross-shaped strength – a strength-in-weakness.
Sometimes this strength will be “eagle’s wings” (see here for more on “eagles wings”). Sometimes it will be running with endurance. And sometimes it will be just enough to walk “and not faint”. But at all points it will be the LORD Jesus who upholds us.
You can run in your own strength and you will run yourself into the ground. Or you can stop the self-justification. You can swap human strength for Christ’s, and simply run in His good pleasure.