He becomes the victim of his own destructive plans ¹  and the violence he intended for others falls on his own head. ² 

What benefit ¹  do people ²  get from all the effort which ³  they expend ⁴  on earth? ⁵ 

What does a man acquire from all his labor and from the anxiety that accompanies his toil on earth? ¹ 

and also that everyone should eat and drink, and find enjoyment in all his toil, for these things ¹  are a gift from God.

A song of ascents, ²  by Solomon. If the Lord does not build a house, ³  then those who build it work in vain. If the Lord does not guard a city, ⁴  then the watchman stands guard in vain.

I have seen personally what is the only beneficial and appropriate course of action for people: ¹  to eat and drink, ²  and find enjoyment in all their ³  hard work ⁴  on earth ⁵  during the few days of their life which God has given them, for this is their reward. ⁶ 

A man who is all alone with no companion, ¹  he has no children nor siblings; ²  yet there is no end to all his toil, and he ³  is never satisfied with riches. He laments, ⁴  “For whom am I toiling and depriving myself ⁵  of pleasure?” ⁶  This also is futile and a burdensome task! ⁷