body
kidneys
כליות · עצה · טוחות
Bottom line
Kilayos is the plain word for kidneys, and in a pasuk about Hashem searching a man it is his innermost thoughts. Tuchos is a poetic word for the same organ, so render it kidneys with Chazal, or innards with Ibn Ezra. Atzeh is a hapax and genuinely disputed: kidneys on the Gemara's reading, the base of the spine on Targum Onkelos's; say which you follow. Note that both kilayos and tuchos appear only in the plural.
At a glance
| Hebrew | translit | English | what sets it apart |
|---|---|---|---|
| כליות | kilayos | kidneys | the ordinary word, and the seat of a man's hidden motives |
| עצה | atzeh | kidneys / base of the spine | hapax, Vayikra 3:9; disputed (Chullin 11a against Targum Onkelos) |
| טוחות | tuchos | kidneys | poetic, twice only; from ט-ח, "smooth" (Rashi) or "smeared" (Radak) |
Where the authorities disagree
What atzeh is (Vayikra 3:9, the fat taken "opposite the atzeh"). Chullin 11a reads it as the kidneys, on the strength of Berachos 61a, that the two kidneys give eitzah to the heart, one advising for good and one for bad (Koheles 10:2 putting the good counsel on the right); Rashi (to Shemos 29:22 and Vayikra 3:9) and Rashbam follow, and the column notes that the derashah appears to rest on the spelling עצה, which can be read eitzah. Rabbi Elazar Rokeach of Worms, a late twelfth-century Ashkenazic scholar, adds when citing this tradition (Sodi Razi) that the kidneys are also the source of happiness, from v'sa'alozna kilyosai (Mishlei 23:16). Against them, Targum Onkelos (to Vayikra 3:9; see Meleches Shlomo to Chullin 3:1), Sefer HeAruch, Sefer HaTishbi, Ibn Janach, and Radak read it as the end of the spine, the last two taking the root as ע-צ-ה while granting that Chazal read it as from י-ע-צ. Ibn Ezra says only that the sense must be gleaned from context, and rejects any link to eitz, "tree," which is what Menachem Ibn Saruk implies by filing atzeh under ע-צ, and what Rabbeinu Bachya, Shadal, and Rabbi Shlomo Pappenheim say outright: the spine with its ribs looks like a trunk with branches. Keep both readings; the sugya and the Targum are each authoritative in their own domain.
Why atzeh would mean kidneys at all. Rabbi Shes ben Yefes HaRofeh of Aleppo (Chemas HaChemdah to Vayikra 3:17): they filter the blood and cleanse the flesh, letting the head and heart work properly, which sharpens a man's thinking the way good advice does. He offers as an alternative that atzeh is literally marrow inside a bone, and by extension the brain in the skull and the kidneys in the body. The column adds a suggestion of its own, that the kidney is an atzeh because its work is filtering, and advice too is a filtering of good ideas from bad. (It points the reader for the scientific side of the kidneys-and-thought question, and its bearing on transplants, to Rabbi Natan Slifkin's monograph "The Question of the Kidneys' Counsel.")
What tuchos is. Rosh Hashanah 26a, with Targum, Rashi, and Radak: the kidneys. Ibn Ezra (to Iyov 38:36) differs slightly, preferring the innards generally rather than the kidneys specifically, which the column says comes to much the same. Others read the word as a fowl, an ibis or some such bird, or as darkness; the column cites for this Daas Mikra (to Iyov 38:36), the Brown-Driver-Briggs Hebrew lexicon, and David J. A. Clines' Dictionary of Classical Hebrew. Part of the question turns on whether the sechvi beside it (Iyov 38:36) is the heart or a rooster.
Where tuchos comes from. Machberes Menachem and Rashi (to Tehillim 51:8 and Rosh Hashanah 26a): from ט-ח, "smooth," the root also of mitachavei, a target (Bereishis 21:16), since an arrow needs a clear run at its mark. Radak, Rabbi Avraham Ibn Ramoch, and Metzudas Zion: from the "smearing" sense of the same root, since the kidneys are coated in fat. Chochmas Manoach merges the two.
Distinctions
kilayos (כליות)
Thirty-one times in Tanach, fifteen of them the rule that an animal's kidneys are burned on the mizbeiach with its fats (Vayikra 3:4, 3:10, 4:9, 8:16, 8:25, 9:10, 9:19, and parallels), and again in the Mishnah (Chullin 3:2, 4:1; Tamid 4:3). In the abstract sense it is a man's hidden motives, which Hashem alone examines, "testing the heart and the kidneys" (Yirmiyahu 11:20, 17:10, 20:12; Tehillim 7:10). Three derivations: Rabbi Moshe Tedeschi-Ashkenazi (Otzar Nirdafim 344) links it to kele, imprisonment, spelled with a final aleph, since these organs sit shut away deep inside, which fits Ibn Ezra's reading (to Tehillim 7:10) that kilayos can mean the thoughts hidden in a man. Ibn Ezra elsewhere (to Shemos 23:25, Vayikra 3:4; Tehillim 16:7, 139:13, cited by Radak in Sefer HaShorashim) postulates that the kidneys are the seat of libidinous desire and the word a cognate of כ-ל-ה, "to long for" (Shmuel II 13:39); Rav Hirsch (to Shemos 23:18 and Vayikra 3:4) says the same, that they are the deepest source of sensuous desire and so the organs of the evil impulses, and Ramban (to Vayikra 1:9) explains on that basis why burning them is central to atonement, since they are the instruments of the desire that caused the sin. Rabbi Shlomo Pappenheim (Cheshek Shlomo) takes a third path, from the biliteral כ-ל, "totality," which also gives kol and kli, a vessel that surrounds what is put in it: the kidneys are the vessel holding filtered waste until it is expelled. In the Gemara the singular is kulya.
the wheat of Devarim 32:14
"The fat of the kilyos of wheat" is a distinct usage. Rashi: wheat so plump each kernel was like a kidney, fulfilled in Shlomo's day, though Kesubos 111b takes it of the Time to Come, when kernels will be the size of a large ox's kidneys. Chizkuni: the choicest wheat, from the sense of a man's innermost wants. Radak: simply that the kernels are kidney-shaped, as English "kidney beans" are named.
tuchos (טוחות)
"Behold, You desire truth in the tuchos" (Tehillim 51:8), and "who put wisdom in the tuchos, who gave understanding to the sechvi" (Iyov 38:36). Like kilayos, it is never singular.
Rendering guidance
- Korbanos context: כליות is "kidneys," flatly. Do not reach for "reins," the old English rendering the column notes is often used (it is kin to English renal and adrenaline); it is now unreadable.
- Where Hashem "tests the heart and the kidneys," keep "kidneys" and gloss; the derashos depend on the anatomy.
- Trap: English "kidneys" would absorb all three words and hide the machlokes at Vayikra 3:9. Render עצה as "kidneys" or "base of the spine" with a note naming Chullin 11a against Targum Onkelos, never silently.
- טוחות is poetic. "Inmost being" reads well in Tehillim 51:8, but a translation that is tracking Chazal should keep "kidneys" and gloss.
- כליות חטה (Devarim 32:14) is "kidney-fat of wheat" or "the choicest of the wheat," depending on whether Rashi or Chizkuni is being followed.
Sources
Rabbi Reuven Chaim Klein, "Vayikra: The Kidneys Advisory," What's in a Word?, Ohr Somayach, 13 Adar II 5784 (2024-03-23): raw text in sources/whats-in-a-word/raw/11307-vayikra-the-kidneys-advisory.md. The article's list of the korbanos loci prints "Lev. 2:15" and "4:7"; the fifteen instances run through Vayikra 3-9. Primary loci: Vayikra 1:9, 3:4, 3:9, 3:10, 3:17, 4:9, 8:16, 8:25, 9:10, 9:19; Shemos 23:18, 23:25, 29:22; Bereishis 21:16; Devarim 32:14 with Rashi and Chizkuni; Yirmiyahu 11:20, 17:10, 20:12; Tehillim 7:10, 16:7, 51:8, 139:13; Mishlei 23:16; Iyov 38:36; Koheles 10:2; Berachos 61a; Chullin 11a; Chullin 3:2 and 4:1, Tamid 4:3; Rosh Hashanah 26a; Kesubos 111b; Sefer HaShorashim; Machberes Menachem; Sefer HeAruch; Sefer HaTishbi; Meleches Shlomo to Chullin 3:1; Otzar Nirdafim 344; Cheshek Shlomo; Sodi Razi; Chemas HaChemdah; Chochmas Manoach; Daas Mikra to Iyov 38:36; the Brown-Driver-Briggs lexicon and Clines' Dictionary of Classical Hebrew (which the article cites for the "fowl" and "darkness" readings of tuchos); Rabbi Natan Slifkin's monograph on the kidneys' counsel. For כ-ל-ה, "to long for," the article's list is Shmuel II 13:39, Tehillim 119:3 and 119:81; only 13:39 and 119:81 carry the root, and Tehillim 119:3 does not, so it is not repeated above.