Verse explainer

What does Isaiah 40:29 really mean?

God's strength isn't a reward for the strong — it flows specifically to those who have run completely out.

KJV

He giveth power to the faint; and to them that have no might he increaseth strength.

BSB

He gives power to the faint and increases the strength of the weak.

The plain meaning

Isaiah 40 is addressed to exhausted exiles who feared God had forgotten them (v. 27). The prophet's answer builds in stages: God himself never tires (v. 28), and precisely because he doesn't, he can pour energy into those who do. The recipients named here are the faint and those with no might — not the capable, not the spiritually impressive. The logic is almost paradoxical, as Jamieson, Fausset & Brown note: the very admission of having no strength is the condition under which God increases it. Verse 31 extends this into the famous eagle-wings promise, but the foundation is here in v. 29 — the gift goes to the depleted, not the deserving. This is not a general motivational promise about human resilience; it is a specific assurance tied to God's own inexhaustible nature, introduced in v. 28.

The common misreading

"God gives strength to those who keep going" — a promise for the persistent and disciplined. The verse is frequently quoted as fuel for effort — a divine energy drink for people in the middle of striving. Motivational uses almost always frame the recipient as someone pressing through difficulty, someone who deserves a boost for their faithfulness. But Isaiah's word for the recipient is ya'ef — faint, spent, used up — and the second half of the verse makes it explicit: 'to them that have no might.' The qualifying condition is not persistence; it is depletion. Verse 30 sharpens this further: even the young and strong 'shall faint and be weary' and 'utterly fail.' No natural strength qualifies you. The promise is structured as a direct consequence of God's own inexhaustibility introduced in v. 28 — because he never runs out, he can give to those who already have. Read as motivation for the striving, the verse flatters self-reliance. Read as Isaiah wrote it, it is a word for people who have stopped — who feel disqualified by their own weakness — telling them that their emptiness is precisely where this promise applies.

What the commentators say

Jamieson, Fausset & Brown19th c. · PD

JFB draws a direct contrast between vv. 28 and 29: God 'does not faint,' and the immediate implication is that he can give to those who do. They note the apparent paradox — those with 'no might' receive increased strength — and connect it to Paul's teaching that divine power is made perfect in weakness (2 Cor 12:9). The gift is not supplemental to human effort; it arrives where human effort has collapsed.

John Gill18th c. · PD

Gill situates the verse in a pattern of contrast: even the young and naturally strong faint and fall (v. 30), so the promise of v. 29 cannot rest on any native capacity. He applies the passage broadly — to Israel in captivity, to the persecuted church — anywhere God's people find themselves outmatched and spent. The point is that human strength is never the qualifying condition; its absence is.

Charles Spurgeon19th c. · PD

Spurgeon returns to this verse repeatedly in his sermons on affliction, emphasizing that the promise is addressed to the 'faint' by name — not those who are merely tired, but those who have given out entirely. He treats the verse as a pastoral comfort specifically for believers who feel too weak to pray, too weary to trust, insisting the very condition they're ashamed of is the one the text addresses.

The word behind it

יָעֵף ya'ef

'Faint' or 'exhausted' — the root conveys weariness to the point of giving out, not mere tiredness. It is the same family of words used in v. 30 for the young men who 'utterly fail.' The prophet chooses a word for depletion, not inconvenience. This matters because the popular reading turns the verse into encouragement for people pushing hard; the actual word targets those who have already stopped — who have nothing left to push with.

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