But those who wait on 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. (Isaiah 40:31—NKJV)

Isaiah chapter 40 is one of my personal favorite chapters in the Scriptures. The entire chapter is designed to bring comfort to God’s distressed people. Isaiah proclaims God’s purpose to redeem (1–11), God’s power to deliver (12–26), and God’s promise to sustain (27–31). This knowledge about God is powerful for every distressed believer. The chapter points out that there is no real strength of men, no wisdom that God lacks, no nation of might, no supposed god of man, and no true rival of the God of Israel that a believer needs to fear. The Sovereign God of the Bible is entirely unique since He is the only God that is!

The prophet then asks the faithful strugglers why they presume to say that God cannot see the thorny way over which they must travel or that God is unjust toward them (verse 27). There is not a generation of believers finding itself in the thick of the “Slough of Despond,” which has not entertained the notion that God has forgotten them. It is to this feeble, fretful, fearful, yet faithful band of brothers that Isaiah speaks his words of comfort and promise.

He begins his instruction focused on the Dynamo that God is (verse 28). He is everlasting, He is Jehovah, He is the Creator of the very farthest reaches of the earth. His very nature is one which never tires or grows weary through overexertion. His energies are applied with perfect wisdom! None of us has the slightest idea of how significant this nature of God is. We grow weary and, over time, wear out. Our lives are full of beginnings and endings. For far too much of our spiritual lives, we think only in those terms. We are like a machine which must be recharged to work. Without regular maintenance, we outlive our usefulness. We need sustaining power and divine maintenance.

Verse 29 teaches that God is the One who gives power to the weary and to those with no might He increases strength. As believers grow weary in the running of life, He stands ready to come to their aid and to give them their second wind, empower them to endure, and strengthen them to “pour on the coal.”

Lest one beleaguered believer should say he can go it alone, Isaiah gently reminds us all of the reality of fallen human existence—even the strongest among us grows weary and stumbles to the dust (verse 30). “Youths” and “young men” are Hebrew terms used in Scripture to describe the “mighty men” of Israel. No man has an inexhaustible reservoir of strength, stamina, and indefatigable good attitude. The same is true in the spiritual realm.

Isaiah then teaches the mechanism by which God applies His strength to weary believers. The key is to wait, trust, hope, and patiently long for the Lord Jehovah. Isaiah 30:15 enlighteningly reads, “In returning and rest you shall be saved; in quietness and confidence shall be your strength.” This quiet confidence in God is matched by God with “renewing” strength. The thought is that God exchanges strength for your confidence. In this strength the believer finds he gains wings for flying (the Hebrew word picture here is of an eaglet whose wings become endowed with feathers fit for flying). The beleaguered believer gains strength to run the distance—laboring on in useful toil for God—and will march on without fainting! Micah 4:5 states, “For all people walk each in the name of his god, but we will walk in the Name of the Lord our God forever and ever.”

Do you depend upon yourself to persevere in righteousness? Do you live like you depend largely upon your own resources? Or, do you practice the habit of expectant waiting and quiet confidence in the Lord God alone, especially in the tough times? Trust and obey.