kid'-niz (always in the plural:
kelayoth; nephroi; Latin renes, whence the English "reins"): "Reins" and "kidneys" are synonyms, but the King James Version undertook a distinction by using the former word in the figurative, the latter in the literal passages. the English Revised Version has followed the King James Version exactly, but the American Standard Revised Version has retained "reins" only in Job 16:13;Lamentations 3:13; Revelation 2:23, elsewhere substituting "heart," except in Psalms 139:13, where "inward parts" is used. the King James Version and the English Revised Version also have "reins" for chalatsayim, in Isaiah 11:5 (the American Standard Revised Version "loins"). The physiological function of the kidneys is not referred to in the Bible, but has been introduced (quite wrongly) by the King James Version margin to Leviticus 15:2; 22:4.
(1) The kidneys owe their importance in the Bible partly to the fact that they are imbedded in fat, and fat of such purity that fat of the kidneys was a proverbial term for surpassing excellence (Deuteronomy 32:14 margin). For the visceral fat was the part of the animal best adapted for sacrificial burning, and hence, came to be deemed peculiarly sacred (Leviticus 7:22-25; 1 Samuel 2:16). Accordingly, the kidneys with the fat surrounding them were burned in every sacrifice in which the entire animal was not consumed, whether in peace (Leviticus 3:4,10,15; 9:19), sin (Exodus 29:13; Leviticus 4:9; 8:16; 9:10), or trespass, (Leviticus 7:4) offerings; compare the "ram of consecration" (Exodus 29:22; Leviticus 8:25). So in Isaiah 34:6, "fat of the kidneys of rams" is chosen as a typical sacrificial term to parallel "blood of lambs and goats."
(2) The position of the kidneys in the body makes them particularly inaccessible, and in cutting up an animal they are the last organs to be reached. Consequently, they were a natural symbol for the most hidden part of a man (Psalms 139:13), and in Job 16:13 to "cleave the reins asunder" is to effect the total destruction of the individual (compare Job 19:27; Lamentations 3:13). This hidden location, coupled with the sacred sacrificial use, caused the kidneys to be thought of as the seat of the innermost moral (and emotional) impulses. So the reins instruct (Psalms 16:7) or are "pricked" (Psalms 73:21), and God can be said to be far from the reins of sinners (Jeremiah 12:2). In all of these passages "conscience" gives the exact meaning. So the reins rejoice (Proverbs 23:16), cause torment (2 Esdras 5:34), or tremble in wrath (1 Macc 2:24). And to "know" or "try the reins" (usually joined with "the heart") is an essential power of God's, denoting His complete knowledge of the nature of every human being (Psalms 7:9; 26:2; Jeremiah 11:20; 17:10; 20:12;Wisdom of Solomon 1:6; Revelation 2:23). See FAT; PSYCHOLOGY; SACRIFICE. Compare RS2, 379-80, and for Greek sacrificial parallels Journal of Philology, XIX (1890), 46. The anatomical relations are well exhibited in the plate in Sacred Books of the Old Testament, "Leviticus."
Burton Scott Easton