Charles Ellicott Commentary Ecclesiastes 1:3-11

"What profit hath man of all his labor wherein he laboreth under the sun? One generation goeth, and another generation cometh; but the earth abideth for ever. The sun also ariseth, and the sun goeth down, and hasteth to its place where it ariseth. The wind goeth toward the south, and turneth about unto the north; it turneth about continually in its course, and the wind returneth again to its circuits. All the rivers run into the sea, yet the sea is not full; unto the place whither the rivers go, thither they go again. All things are full of weariness; man cannot utter [it]: the eye is not satisfied with seeing, nor the ear filled with hearing. That which hath been is that which shall be; and that which hath been done is that which shall be done: and there is no new thing under the sun. Is there a thing whereof it may be said, See, this is new? it hath been long ago, in the ages which were before us. There is no remembrance of the former [generations]; neither shall there be any remembrance of the latter [generations] that are to come, among those that shall come after." — Ecclesiastes 1:3-11 (ASV)

Man is perpetually toiling, yet from all his toil, no lasting result remains. The natural world exhibits a spectacle of unceasing activity, with no real progress. The sun, the winds, the waters, are all in motion, yet they merely repeat their course, and nothing comes of it.