I the Preacher was king over Israel in Jerusalem.

And I gave my heart to seek and search out by wisdom concerning all things that are done under heaven: this sore travail hath God given to the sons of man to be exercised therewith.

I have seen all the works that are done under the sun; and, behold, all is vanity and vexation of spirit.

I communed with mine own heart, saying, Lo, I am come to 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.

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

For in much wisdom is much grief: and he that increaseth knowledge increaseth sorrow.