So if a man lives many years, let him rejoice in them all. But let him remember the days of darkness, for they will be many. Everything to come is futile.
Here is an admonition both to old people and to young people, to think of dying, and get ready for it. Having by many excellent precepts taught us how to live well, the preacher comes now, towards the close of his discourse, to teach us how to die well and to put us in mind of our latter end. I.
Commenting on Ecclesiastes 11:7-10
But if a man live many years,.... Enjoying light and life, and beholding the sun with much delight and pleasure. The days of men on earth, or under the sun, are but few at most; but some live many days, in comparison of others; they come to a good old age, as Abraham did; and to their graves like a shock of corn fully ripe...
But while man thankfully enjoys life, "let him remember" it will not last for ever. The "many days of darkness," that is, the unseen world (Job 10:21-22; Psa 88:12), also days of "evil" in this world (Ecc 11:2), are coming; therefore sow the good seed while life and good days last, which are not too long for accomplishing life's duties.