Mirth. That is, living for pleasure. This suggests the eclipse of Solomon’s faith by a materialistic point of view.
Eat. The activities here listed are not wrong in themselves. God gave man the capacity to eat, drink, and enjoy the good things life has to offer. Solomon’s meaning here, however, is that inasmuch as self-control and denial of appetite had apparently brought no reward, he had, at one time, concluded that it is better to live to satisfy the senses, to extract everything possible from the material things of life.
Merry. Heb. samach, “to be glad,” “to rejoice.”
Shall abide. Solomon continues his description of the feelings that once overwhelmed him.