Endurance
Isaiah 40:31
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.
The order of the three images is the interesting part, because it goes downwards. Mounting up like eagles, then running, then walking. If you were building this to inspire, you would run it the other way and finish on the eagles.
It finishes on walking instead, and on not fainting. Which suggests the writer knew which of the three most people actually need. Flying is rare. Most of a life is walking, and the promise attached to walking is the least dramatic and the most load-bearing.
“Wait” is not passivity here. The word carries expectation, the way you wait for someone you are certain is coming.