Reuben is the first son of Jacob and Leah. His name comes from a sentence of his mother: "for G-d has seen my affliction; now my husband will love me" (Genesis 29:32). The name carries the verb to see, ra'ah: he is the son through whom Leah knows she is seen.
Jacob blesses him first: "Reuben, you are my firstborn, my strength and the first of my vigor, excelling in dignity and excelling in power." But he adds at once: "unstable as water, you shall not excel, for you went up to your father's bed" (Genesis 49:3 and 4), recalling the episode of Bilhah (Genesis 35:22). The blessing acknowledges the firstborn's strength and takes the first rank away from him.
Moses says only: "Let Reuben live and not die, and let his men be numbered" (Deuteronomy 33:6). No kingship, no land named: to live, to last, not to disappear.
On the breastplate his stone opens the first row: the odem, whose name means red. Rashi writes it plainly: "odem for Reuben" (Rashi on Exodus 28:21). It is often translated as sardius or carnelian, but the identification of the biblical stones remains uncertain. In the desert Reuben leads the southern camp, with Simeon and Gad (Numbers 2:10 to 16), and sets out second. Ramban explains that he was placed in the south, next to Judah, "in honor of the birthright." Ibn Ezra reports that his banner bore the figure of a man, and Ramban adds the mandrakes Reuben had found in the field (Genesis 30:14).
According to the order of the banners, Reuben receives Tamuz, which Sefer Yetzirah makes the month of the letter Chet (5:2); in the Vilna Gaon's version, Chet rules over sight. The Bnei Yissaschar notes the match: Leah named this son with a word of seeing, "for G-d has seen," and the first letter of Reuben is that of re'iyah, sight. But the attribution varies: according to the order of birth, cited by the Shem MiShmuel, Reuben receives Nissan, and again it is sight that makes the link.
Keep this: Reuben's blessing begins with strength and ends with a limit. The firstborn keeps his life, his name and his place of honor in the south; the first rank passes to another.
