Ecclesiastes 1:4 - Joseph Benson’s Commentary on the Old and New Testaments

One generation passeth away, &c. Men continue but for one, and that a short age, and then they leave all their possessions, and therefore they cannot be happy here, because the source of happiness must needs be unchangeable and eternal, and the certain knowledge of the approaching loss of all these things must rob a man of solid contentment in them. But the earth abideth Through all successive generations of men; and therefore man is more mutable than the very earth upon which he stands, and which, together with all the comforts which he enjoyed in it, he leaves behind him to be possessed by others.