Isaiah 40:29

He giveth power to the faint,.... Who are ready to faint under afflictions, because they have not immediate deliverance, or their prayers are not answered at once, or promises not fulfilled as they expected; to such he gives fresh supplies of spiritual strength; he strengthens their faith, and enlarges their views, to behold the goodness of the Lord in the land of the living, and confirms his blessings and promises of grace unto them, Psalms 27:13. The Targum is,

"who giveth wisdom to the righteous that breathe after the words of the law:''

and to them that have no might he increaseth strength; not that they have no might at all, strictly speaking; for then it could not be properly said their strength was increased by him; but that their might and power were very small, and that in their own apprehensions they had none, and then it is that fresh strength is given them; as the apostle says, "when I am weak, then am I strong"; 2 Corinthians 12:10, though this may be understood, not of the strength of their graces, but of their sins and corruptions: a word from the same root as this here used signifies "iniquity"; and the sense may be, that the Lord increases the spiritual strength of such on whom the lust's, corruptions, and virtuosity of nature have not the power and dominion e.

e "Cur non sumatur", אונים "illis quibus non sunt vitiosae concupiscentiae robur auger", Gusset. Ebr. Comment. p. 21.