Ecclesiastes 1:17; Ecclesiastes 2:22; Ecclesiastes 4:16

17 And I gave my heart to know wisdom, and to know madness and folly: I perceived that this also is vexation of spirit.

22 For what hath man of all his labour, and of the vexation of his heart, wherein he hath laboured under the sun?

16 There is no end of all the people, even of all that have been before them: they also that come after shall not rejoice in him. Surely this also is vanity and vexation of spirit.