Ecclesiastes 4:4; Ecclesiastes 4:7-8

4 Again, I saw that for all toil and every skillful work a man is envied by his neighbor. This also is vanity and grasping for the wind.

7 Then I returned, and I saw vanity under the sun:

8 There is one alone, without companion: He has neither son nor brother. Yet there is no end to all his labors, Nor is his eye satisfied with riches. But he never asks, "For whom do I toil and deprive myself of good?" This also is vanity and a grave misfortune.