Ecclesiastes 4:4, 8, 16

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.

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.

There is no end of all the people, even of all that have been before them: they also that come after shall not rejoice in him. Surely this also is vanity and vexation of spirit.