Eccl.1.18

Ecclesiastes 1:18

KJV

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

Ecclesiastes 2:23

KJV

For all his days are sorrows, and his travail grief; yea, his heart taketh not rest in the night. This is also vanity.

Ecclesiastes 12:12

KJV

And further, by these, my son, be admonished: of making many books there is no end; and much study is a weariness of the flesh.