Ecclesiastes 2:15; Ecclesiastes 2:19; Ecclesiastes 7:16; Ecclesiastes 7:23

15 Then said I in my heart, As it happeneth to the fool, so it happeneth even to me; and why was I then more wise? Then I said in my heart, that this also is vanity.

19 And who knoweth whether he shall be a wise man or a fool? yet shall he have rule over all my labour wherein I have laboured, and wherein I have shewed myself wise under the sun. This is also vanity.

16 Be not righteous over much; neither make thyself over wise: why shouldest thou destroy thyself?

23 All this have I proved by wisdom: I said, I will be wise; but it was far from me.