Midrash sobre Números 1:10

R. Yohanan said: Where there actually only twelve tribes? Does it not say: Ephraim and Manasseh shall be like Reuben and Simeon (Gen. 48:5), making fourteen in all? The answer is that when Levi is counted among the tribes, they are not counted, and when Levi is not counted among the tribes, Ephraim and Manasseh are reckoned as one tribe. How do we know this It is written: Of the children of Joseph: of Ephraim, Elishama the son of Manasseh … Gamaliel (Num. 1:10). Hence, all these are the twelve tribes—no more and no less.

(Gen. 49:28:) ALL THESE ARE THE TRIBES OF ISRAEL, TWELVE IN NUMBER. These are the tribes, but < it is written > elsewhere about Ishmael (in Gen. 17:20): HE SHALL SIRE TWELVE PRINCES.⁷⁶Tanh., Gen. 12:15; Gen. R. 47:5. As for the tribes, that has a basis in the structure of the world. The day has twelve hours, the night has twelve hours, the year has twelve months, < and there are > twelve planets. R. Johanan said: Were there < really > twelve tribes? Now do not Ephraim and Manasseh make fourteen? It is simply that, when Levi was numbered with them, Ephraim and Manasseh were not numbered with them. Where is it shown? Where it is stated (in the list of Numb. 1:10, which omits Levi): FROM THE CHILDREN OF JOSEPH: FROM EPHRAIM, ELISHAMA BEN AMMIHUD; FROM MANASSEH, GAMALIEL BEN PEDAHZUR. Ergo (in Gen. 49:28): ALL THESE ARE THE TRIBES OF ISRAEL, TWELVE IN NUMBER, no less and no more. Even Rebekah saw {them} [these twelve], as stated (in Gen. 25:23):⁷⁷Cf. Gen. R. 63:6; 97, New Version, on 49:28 (= pp. 1226—1227 in the Theodor-Albeck edition); cf. also PRK 3:1. AND THE LORD SAID TO HER: TWO NATIONS ARE IN YOUR WOMB. Here are two. (Ibid., cont.:) AND TWO PEOPLES < SHALL ISSUE > FROM YOUR BOWELS. Here are four. (Ibid., cont.:) AND ONE PEOPLE SHALL BE STRONGER THAN THE OTHER. Here are six. (Ibid., cont.:) AND THE ELDER SHALL SERVE THE YOUNGER. Here are eight. (Vs. 24:) AND BEHOLD, THERE WERE TWINS IN HER WOMB. Here are ten. (Vs. 22:) AND THE CHILDREN STRUGGLED WITHIN HER. Here are twelve.