I have seen all the works that are done under the sun; and, behold, all is vanity and vexation of spirit.
I have seen all the works (the actions and businesses of men) that are done under the sun; and, behold, all (is) vanity. The reason is here given why wise investigation into man's "works" is only "sore travail" (Ecclesiastes 1:13) - namely, because all man's ways are vain (Ecclesiastes 1:18), and cannot be mended. (Ecclesiastes 1:15).
Vexation of (a preying upon the) spirit, х rª`uwt (H7469) ruwach (H7307)]. Hengstenberg translates [from raa`aah (H7462), to feed; to busy one's self about], 'the pursuit of wind,' as Ecclesiastes 5:16; Hosea 12:1, "Ephraim feedeth on wind;" Isaiah 44:20; Proverbs 15:14. So the Septuagint [proaireris pneumatos] 'a purpose of wind;' an empty striving. But the Vulgate, Chaldaic, and Syriac support the English version.