Ecclesiastes 4:4; Ecclesiastes 4:6; Ecclesiastes 4:16

4 Again I considered all the labours of men, and I remarked that their industries are exposed to the envy of their neighbour: so in this also there is vanity, and fruitless care.
6 Better is a handful with rest, than both hands full with labour, and vexation of mind.
16 The number of the people, of all that were before him is infinite: and they that shall come afterwards, shall not rejoice in him: but this also is vanity, and vexation of spirit.