Alice C. Linsley
Some groups in Genesis are 3-clan confederations (such as Isaac's 3 sons) and others are described as 12-tribe confederations. Nahor, Abraham's older brother, was the progenitor of twelve Aramean tribes through his twelve sons, of whom eight were born to him by Milcah and four by Reumah (Gen. 22.20-24).
Ishmael, Abraham's son by an Egyptian concubine, was the progenitor of twleve Nabatean tribes: "Nebajoth; Kedar, Adbeel, Mibsam, Mishma, Dumah, Massa, Hadar, Tema, Jetur, Naphish, and Kedemah: These are the sons of Ishmael, and these are their names, by their towns, and by their castles; twelve princes according to their nations." (Genesis 25:13-16).
Jacob, a son of Isaac, was the progenitor of twelve Israelite tribes: Reuben, Simeon, Levi, Judah, Issachar, Zebuln, Dan, Naphati, Gad, Asshur, Joseph and Ben-Jamin. There is discrepancy on the number of Israelite tribes. Some count Dinah's line and some count Joseph's two sons Ephraim and Manassah.
There is an attempt to organize Esau into a 12-tribe confederation in Genesis 36:40 but only eleven chiefs are listed. The attempt fails because there are two named Esau. Esau the Elder was the father of Eliphaz. Esau the Younger married Basemath who bore Reuel, and Oholibamah who bore Jeush, Jaalam, and Korah (Genesis 36:1-9). These were the people of Seir, the Horite. They were Horite clans. Their socio-political organization appears to be that of 3 clans.
The 12-tribe organization appears to be the handiwork of a writer influenced by Babylonian thought. It represents an attempt to neatly classify the ruler descendents of Noah according to a celestial pattern. However, the Bible tells us that these rulers intermarried. The lines of Kain and Seth intermarried, as did the lines of Ham and Shem. The lines of Abraham and Nahor also intermarried. This means that socio-political affiliations were less formal than suggested by the 12 tribe organization.
Further, there is evidence that the older organization comprised three sons of the same father. Where three sons appear in Genesis we have a code indicating a joining of three clans or a tribal unity. Perhaps this is why Leah named her third son Levi, meaning "joining" (Gen. 29:34). Likely, Leah hoped that she would be credited (and loved?) by providing Jacob with the three sons necessary to establish a tribe.
The 12-tribe organization is likely imposed by a Mesopotamian source, since it suggests observation of the Moon. Just as the days of the week are named for the seven visible planets, so the number twelve suggests the twelve cycles of the moon to complete a year. Abraham's ancestors never associated the Moon with the Creator. For them the Creator's emblem (boat or chariot) was the Sun. Veneration or worship of the Moon was characteristic of those who lived, not in Canaan, but "beyond the Euphrates". Joshua 24:2 says: “In olden times, your forefathers – Terah, father of Abraham and father of Nahor – lived beyond the Euphrates and worshiped other gods.” The implication is that Terah, whose ancestors came from Africa and Canaan, fell into worshiping contrary to his fathers’ tradition while living “beyond the Euphrates.” This is historically accurate since Abraham's Horite ancestors never worshiped the Moon, as was done in Ur and Haran.
The Joshua passage shares with the Deuteronomistic History a common concern with idolatry and places the covenant at Shechem at precisely the location where God appeared to Abraham in 3 Persons (Gen. 18). Here in reference to the Godhead, the number three speaks of one-ness or unity.
There is more evidence in the Bible for the 3-clan organization than for the 12-tribe organization. Consider the Horite confederations of Uz, Huz and Buz and Magog Og and Gog. Here are some of the 3-clan confederations listed in Scripture:
Cain Abel Seth (Gen. 4-5)
Ham Japeth Shem (Gen. 5-9)
Og Gog Magog (Gen. 10 and Nu. 21:33)
Haran Nahor Abraham (Gen. 11-12)
Ishmael Jokshan Isaac (Gen. 16, 21, and 25)
Jeush Jalam Korah (Gen. 36: 4-18)
Korah Moses Aaron (Ex. and Nu.)
Dedan Tema Buz (Jeremiah 25)
The Jebusite confederation is Yoruba, Egba and Ketu. In Canaan, the 3-clan Jebusite confederation consisted of Sheba, Jebu and Joktan.
Among the Sara of Chad, Sudan and Somalia the confederation is comprised of the qir ka, the qin ka, and the qel ka. The Sara are descendents of the Sao, an earlier 3-tribe confederation of warriors and kingdom builders. According to legend, there were giants among them.
Martin Noth, in his seminal work "The Scheme of the Twelve Tribes of Israel" (1930), showed that the Twelve Tribes of Israel did not exist prior to the covenant assembly at Shechem described in the book of Joshua.