Isaiah chapter 40 opens the second part of the book, a message of comfort for the people exiled in Babylon. In contrast with idols that can do nothing, God is presented as all-powerful and incomparable. Verse 31 brings a beloved promise: those who wait on the Lord will renew their strength, mount up with wings as eagles, run and not be weary, walk and not faint. Waiting on God is not passivity but active trust, resting in the Lord's faithfulness. When our strength runs out, he gives us renewed vigor. Today those who feel exhausted can find in this promise a fresh impulse to keep going.