Albert Barnes Commentary Ecclesiastes 8:15

"Then I commended mirth, because a man hath no better thing under the sun, than to eat, and to drink, and to be joyful: for that shall abide with him in his labor [all] the days of his life which God hath given him under the sun." — Ecclesiastes 8:15 (ASV)

Mirth - A better term is Gladness, or “joy” . The Hebrew word is applied not only to the pleasures arising from the physical senses, but also frequently to religious joy.

The sentiment of this verse is a frequent conclusion of the writer’s personal experience (compare marginal references) and is unfairly charged with Epicureanism. The Preacher is careful to set forth pleasure as a gift from God, to be earned by labor, and received with thankfulness to the Giver, and to be accounted for to Him. His estimate of the pleasures of the senses is recorded in Ecclesiastes 7:2-6.