1Ch 1:38-42
When Esau with his descendants had settled in Mount Seir, they subdued by degrees the aboriginal inhabitants of the land, and became fused with them into one people. For this reason, in Gen 36:20-30 the tribal princes of the Seirite inhabitants of the land are noticed; and in our chapter also, 1Ch 1:38, the names of these seven שׂעיר בּני, and in 1Ch 1:39-42 of their sons (eighteen men and one woman, Timna), are enumerated, where only Aholibamah the daughter of Anah, also mentioned in Gen 36:25, is omitted. The names correspond, except in a few unimportant points, which have been already discussed in the Commentary on Genesis. The inhabitants of Mount Seir consisted, then, after the immigration of Esau and his descendants, of twenty tribes under a like number of phylarchs, thirteen of whom were Edomite, of the family of Esau, and seven Seirite, who are called in the Chronicle שׂעיר בּני, and in Genesis חרי, Troglodytes, inhabitants of the land, that is, aborigines.
If we glance over the whole posterity of Abraham as they are enumerated in 1Ch 1:28-42, we see that it embraces (a) his sons Ishmael and Isaac, and Isaac’s sons Israel and Esau (together 4 persons); (b) the sons of Ishmael, or the tribes descended from Ishmael (12 names); (c) the sons and grandsons of Keturah (13 persons or chiefs); (d) the thirteen phylarchs descended from Esau; (e) the seven Seirite phylarchs, and eighteen grandsons and a granddaughter of Seir (26 persons). We have thus in all the names of sixty-eight persons, and to them we must add Keturah, and Timna the concubine of Eliphaz, before we get seventy persons. But these seventy must not by any means be reckoned as seventy tribes, which is the result Bertheau arrives at by means of strange calculations and errors in numbers.
Upon this conclusion he founds his hypothesis, that as the three branches of the family of Noah are divided into seventy peoples (which, as we have seen before is not the case), so also the three branches of the family of Abraham are divided into seventy tribes; and in this again he finds a remarkable indication “that even in the time of the chronicler, men sought by means of numbers to bring order and consistency into the lists of names handed down by tradition from the ancient times.”