Ecclesiastes 4:7 - Ellicott's Commentary On The Whole Bible

Then I returned. — The vanity of toil is especially apparent in the case of a solitary man. It is possible, as has been suggested (see Ecclesiastes 2:18), that this may have been the writer’s own case. The following verses, which speak of the advantages of friendship and unity, are of a more cheerful tone than the rest of the book.