Albert Barnes Commentary Ecclesiastes 1:4

"One generation goeth, and another generation cometh; but the earth abideth for ever." — Ecclesiastes 1:4 (ASV)

Vanity is shown in mankind, the elements, and all that moves on earth; the same course is repeated again and again without any permanent result or real progress, and events and people alike are forgotten.

Abides - The apparent permanence of the earth increases by contrast the transitory condition of its inhabitants.

Ever - The word does not here absolutely signify “eternity” (Compare to Ecclesiastes 3:11 note), but a certainly short period : here it might be paraphrased “as long as this world, this present order of things, lasts.”