Isaiah 40:29

27 Why do you say, O Jacob, and why do you assert, O Israel, “My way is hidden from the LORD, and my claim is ignored by my God”?

28 Do you not know? Have you not heard? The LORD is the everlasting God, the Creator of the ends of the earth. He will not grow tired or weary; His understanding is beyond searching out.

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

30 Even youths grow tired and weary, and young men stumble and fall.

31 But those who wait upon the LORD will renew their strength; they will mount up with wings like eagles; they will run and not grow weary, they will walk and not faint.

Do read the surrounding verses too, because the context often says more than a single verse.

Compare

BSB
He gives power to the faint and increases the strength of the weak.
KJV
He giveth power to the faint; and to them that have no might he increaseth strength.
WEB
He gives power to the weak. He increases the strength of him who has no might.
ASV
He giveth power to the faint; and to him that hath no might he increaseth strength.
DARBY
He giveth power to the faint; and to him that hath no might he increaseth strength.
BLB
He gives power to the weary, and to those with no might, He increases strength.
ÅB
Han gir den trette kraft, og den som ingen krefter har, gir han stor styrke.
OTB
Han gir styrke til den trette og øker kraften til den svake.
B1930
Han gir den trette kraft, og den som ingen krefter har, gir han stor styrke.

Study notes (Tyndale)

Original text and word study

Cross references