Solomon
Ecclesiastes 7:25ESV·traditional attribution

I turned my heart to know and to search out and to seek wisdom and the scheme of things, and to know the wickedness of folly and the foolishness that is madness.

Matthew Henry Presbyterian @wholebiblehenry

Solomon had hitherto been proving the vanity of the world and its utter insufficiency to make men happy; now here he comes to show the vileness of sin, and its certain tendency to make men miserable; and this, as the former, he proves from his own experience, and it was a dear-bought experience.

Commenting on Ecclesiastes 7:23-29

John Gill Reformed Baptist @doctorgill

I applied mine heart to know, and to search, and to seek out wisdom,.... Or, "I and my heart turned about" (h); took a circuit, a tour throughout the whole compass of things; looked into every corner, and went through the circle of knowledge, in order to search and find out what true wisdom is; which is no other than Christ, and a spiritual knowledge...

Jamieson-Fausset-Brown Reformed @jfbcommentary

Literally, "I turned myself and mine heart to." A phrase peculiar to Ecclesiastes, and appropriate to the penitent turning back to commune with his heart on his past life. wickedness of folly--He is now a step further on the path of penitence than in Ecc 1:17; Ecc 2:12, where "folly" is put without "wickedness" prefixed. reason--rather, "the right estimation" of things.