Ecclesiastes 4:4; Ecclesiastes 4:7-8

4 Again, I considered all travail, and every right work, that for this a man is envied of his neighbour. This is also vanity and vexation of spirit.
7 Then I returned, and I saw vanity under the sun. 8 There is one alone, and there is not a second; yea, he hath neither child nor brother: yet is there no end of all his labour; neither is his eye satisfied with riches; neither saith he, For whom do I labour, and bereave my soul of good? This is also vanity, yea, it is a sore travail.