ez (sha'anan, shal'anan, chiefly, "at ease"): Used 19 times in the Old Testament and once in the New Testament, most frequently meaning tranquillity, security or comfort of mind; in an ethical sense, indicating carelessness or indifference with reference to one's moral or religious interests. The prophet Jeremiah used the phrase as an indication of national or tribal indifference: "Moab hath been at ease from his youth" (Jer 48:11); "I am very sore displeased with the nations that are at ease" (Zec 1:15). Frequent allusions are made also by various prophets to individuals or groups of individuals, as "Woe to them that are at ease in Zion" (Am 6:1); "Rise up, ye women that are at ease" (Isa 32:9), and "Tremble, ye women that are at ease" (Isa 32:11).
⇒See the definition of ease in the KJV Dictionary
The word in another form is used also in a verbal sense and to apply to physical ease and comfort, as "My couch shall ease my complaint" (Job 7:13; compare especially 2Ch 10:4,9). Simple mental tranquillity or peace of mind is also expressed by it (Jer 46:27).
The single instance of its use in the New Testament is illustrative of its figurative but most common usage in the Old Testament, where it refers to moral indifference in the parable of the Rich Fool: "Soul .... take thine ease, eat, drink, be merry" (Lu 12:19).
Walter G. Clippinger