Matthew Henry Commentary Ecclesiastes 1:4-8

"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." — Ecclesiastes 1:4-8 (ASV)

All things change, and never rest. Man, after all his labor, is no nearer finding rest than the sun, the wind, or the current of the river. His soul will find no rest, if he does not have it from God. The senses are soon tired, yet still craving what is untried.