Ecclesiastes 4:8; Ecclesiastes 4:16; Ecclesiastes 12:12

8 There was a certain man without a dependent, having neither a son nor a brother, yet there was no end to all his labor. Indeed, his eyes were not satisfied with riches and he never asked, "And for whom am I laboring and depriving myself of pleasure?" This too is vanity and it is a grievous task.

16 There is no end to all the people, to all who were before them, and even the ones who will come later will not be happy with him, for this too is vanity and striving after wind.

12 But beyond this, my son, be warned: the writing of many books is endless , and excessive devotion to books is wearying to the body.