Ecclesiastes 1:12-18 - Qohelet Introduces His Quest

¹² I myself, the Preacher, being king of Israel and Jerusalem, ¹³ applied my mind to seek out and search for the knowledge of all things that are done under heaven. Such travail and labor hath God given to the children of men, to exercise themselves therein. ¹⁴ Thus I have considered all the things that come to pass under the Sun, and lo, they are all but vanity and vexation of mind.

¹⁵ The crooked cannot be made straight, and the faults cannot be numbered.

¹⁶ I communed with mine own heart, saying, "Lo, I am come to a great estate, and have gotten more wisdom, than all they that have been before me in Jerusalem." Yea, my heart had great experience of wisdom and knowledge, ¹⁷ for thereunto I applied my mind: that I might know what were wisdom and understanding, what were error and foolishness. And I perceived that this also was but a vexation of mind:

¹⁸ For where much wisdom is, there is also great travail and disquietness; and the more knowledge a man hath, the more is his care.