Ecclesiastes 4:7-8 NIV

7 Again I saw something meaningless under the sun:
8 There was a man all alone; he had neither son nor brother. There was no end to his toil, yet his eyes were not content1 with his wealth. "For whom am I toiling," he asked, "and why am I depriving myself of enjoyment?" This too is meaningless-- a miserable business!

References for Ecclesiastes 4:8