The strength which is here promised is to abide through days.

“As thy days, so shall thy strength be.” – Deuteronomy 33:25

Not for today only, but for tomorrow, and for every day as every day shall come. The longest and the shortest day, the brightest and the darkest day, the wedding and the funeral day, shall each have its strength measured out, till there shall be no more days. The Lord will portion out to His saints their support even as their days follow each other.

This strength is to be given daily We shall never have two days’ grace at a time…”As thy days, so shall thy strength be”: this secures you a day’s burden and a day’s help, a day’s sorrow and a day’s comfort. After all, what more do we want? If a man has a meal, let him give thanks for it: he does not want two meals at once. If a man has enough for the day, he certainly is not yet in want for tomorrow. He cannot eat tomorrow’s food today; or, if he did, it would injure his health, and be no comfort to him. Let us narrow our vision as to the necessities of daily life, not looking so far ahead as to compress into today more evil than naturally belongs to it; for “Sufficient unto the day is the evil thereof.” Our strength is to be given to us daily. ~ C.H. Spurgeon

https://www.blueletterbible.org/Comm/spurgeon_charles/sermons/2062.cfm