The Torah impresses upon us the size of Og, king of Bashan, by stating, “Behold his bed (eres) is a bed (eres) of iron…nine handbreadths its length and four handbreadths its width” (Deuteronomy 3:11).
In this passage and eight others, the Bible uses “eres” to mean bed. The more common word for bed, however, is “mitah,” which appears close to 30 times in the Bible. The Ramchal (1707-1746) writes that “mitah” and “eres” are synonyms used side by side for poetic effect. They do appear, though, to carry different shades of meaning.
The root of “mitah” is subject to some controversy. Menachem ibn Saruk (920-970) writes that its root is mem-tet; the Radak (1160-1234) writes that it’s either mem-tet-tet or nun-tet-hey; and Rabbi Shlomo Pappenheim of Breslau (1740-1814) writes that it’s tet-hey.
- Aharon Marcus (1843-1916) suggests that the root is the letter tet itself, which, according to him, connotes “movement to the side.” Other words that contain tet and imply such movement are “stiyah” (deviation), “natah” (to incline), “titah” (turn aside), “tata” (broom), “tach” (plastering), and “taah” (erred).
The common denominator between all these roots is the act of inclining or stretching out. The connection is obvious: When a person lies down in bed, he must incline his body. The connection between bed and inclining is present in Greek, too: “Kline” (bed) is derived from “klino” (incline, slant, bend) – which serve as the etymological bases for such English words as “recline,” “incline,” “climax,” “climate,” and “clinic.”
As far as “eres” is concerned: The Rashbam writes that Og’s eres was his crib. He explains that the Torah is telling us that Og was so big and strong even as a baby that he needed a metal crib to contain him; otherwise he would have broken his bed. (In Modern Hebrew, “eres” means cradle and “arisah” a crib – perhaps in partial accordance with this explanation.)
Rabbi Nosson of Rome (1035-1106) writes in Sefer HaAruch that the root ayin-reish–sin/samech (from whence “eres” is apparently derived) is an expression of “mixture.” Hence the word “arisah” (dough), which is a mixture of ingredients kneaded together. In using “arisah” in the context of the halachos of challah, the Torah is teaching us a lesson, say some commentators. Just like one is expected to consecrate dough and set it aside as holy for a kohen, so too one should consecrate one’s bed (eres) – either by consecrating oneself for the service of G-d upon awakening in the morning or by ensuring that the activity of bed (i.e., marital intimacy) is done in a holy and pure way.
Rabbi Yaakov Tzvi Mecklenburg (1785-1865) and Rabbi Samson Raphael Hirsch (1808-1888) point out that “arisah” is sometimes conjugated as a verb (e.g., see Brachos 37b), which implies that its root primarily means mixing or mutual connection. They therefore explain that the primary meaning of “eres” is a bed whose sides are fastened together by multiple strips or bars through the middle and/or is built from woven/layered planks.
Rabbi Shlomo Aharon Wertheimer (1866-1935) suggests that mitah is a bed with a wooden frame while eres is a bed with an iron frame. The Malbim writes that mitah is a generic bed while eres is a customized or fitted bed, such as a bed used by the infirm (Psalms 41:4), children, or especially pampered women (see Proverbs 7:16). Elsewhere, the Malbim writes that mitah is any piece of furniture upon which one lies or reclines (including a sofa or couch), while an eres is specifically a bed.
Other sources appeal to a more esoteric or Kabbalistic way of differentiating between “mitah” and “eres.” Rabbi Aviad Sar-Shalom Basilea (1680-1749) in Emunat Chachamim posits that “mitah” typically denotes the space in which a man and wife engage in intimacy as it represents the proper balance of influencer (men) and receiver (women). He explains that “mitah” is evocative of tzaddikim who maintain the proper balance of influencer and receiver by recognizing their receptive role vis-à-vis G-d. In contrast, “eres” connotes the bed of the wicked, which is why it’s used in connection with the evil Og.
Rabbi Tzvi Hirsch Kaidanover (1648-1712) in Kav HaYashar also associates “eres” with the forces of evil and connects “eres” (with an ayin) to its homophone “eres” (with an aleph), which means “poison” – an allusion to the poisonous snake in the Garden of Eden who first brought sin into the world.