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.
Waiting isn't usually associated with strength. It's associated with the opposite — stalling, powerlessness, time you're forced to sit through rather than use. So it's strange that Isaiah puts waiting at the center of this promise: those who wait for the Lord renew their strength, as if the waiting itself is the mechanism, not an obstacle to it.
The images that follow escalate on purpose — mounting up with wings like eagles, then running without growing weary, then just walking without fainting. Notice the order runs backward from what you'd expect. The eagle flight comes first, the plain walking comes last, as if the hardest-looking thing isn't actually the hardest part. Ordinary endurance, just putting one foot in front of the other without collapsing, is presented as the real test.
If you're exhausted by nothing dramatic, just the slow grind of ordinary days, this verse was written for that kind of tired, not only the crisis kind.
If your exhaustion is more the slow, ordinary kind than the dramatic kind, it's worth asking what waiting, rather than pushing harder, might actually offer you.
A short video on this is coming soon — for now, read on.