Ecclesiastes 1:3

(3) What profit.—The Hebrew word occurs ten times in this book (Ecclesiastes 2:11; Ecclesiastes 2:13; Ecclesiastes 3:9; Ecclesiastes 5:9; Ecclesiastes 5:16; Ecclesiastes 7:12; Ecclesiastes 10:10-11) and nowhere else in the Old Testament, but is common in post-Biblical Hebrew. The oft-recurring phrase “under the sun” is a peculiarity of this book. In other books we have “under heaven.”