Charles H. Spurgeon on Psalms 90:12

Of all arithmetical rules this is the hardest —to number our days. Men can number their herds and droves of oxen and of sheep, they can estimate the revenues of their manors and farms, they can with a little pains number and tell their coins, and yet they are persuaded that their days are infinite and innumerable and therefore do never begin to number them. Who saith not upon the view of another, surely yonder man looketh by his countenance as if he would not live long, or yonder woman is old, her days cannot be many: thus we can number other men's days and years, and utterly forget our own, therefore this is the true wisdom of mortal men, to number their own days. —Thomas Tymme.