Passage
You shall faint, and labour, and young men shall fall by infirmity.
You shall faint, and labour, and young men shall fall by infirmity.
Isaiah 40:28 Knowest thou not, or hast thou not heard? the Lord is the everlasting God, who hath created the ends of the earth: he shall not faint, nor labour, neither is there any searching out of his wisdom.
Isaiah 40:29 It is he that giveth strength to the weary, and increaseth force and might to them that are not.
Isaiah 40:30 You shall faint, and labour, and young men shall fall by infirmity.
Isaiah 40:31 But they that hope in the Lord shall renew their strength, they shall take wings as eagles, they shall run and not be weary, they shall walk and not faint.
The verse centers on "shall", "faint", "labour", "young", "fall", and "infirmity". It is saying that the verse draws attention to "shall" and "faint", so its meaning should be read from those terms before moving to application.
The nearby context moves from verse 29's "It is he that giveth strength to..." into verse 31's "But they that hope in the Lord...", so "shall" and "faint" belong inside that flow. In Isaiah context, the local focus is the Holy One of Israel, judgment and restoration, the servant of the LORD, and Zion's hope.
A plain takeaway is to answer the verse's own emphasis on "shall" and "faint" with trust shaped by these words, not by a vague optimism outside the passage.