Midrasch zu Jeschijahu 30:2

(Ib., ib., ib.) Now Hebron had been built seven years before Zo'am in Egypt. What does was built mean? Can it be taken literally? How is it possible that a man should build a house for his minor son, before he builds one for his grown-up son? For it is written (Gen. 10, 6) And the sons of Ham: Cush, Mizrayim, and Put, and Canaan. [Hence we see that Canaan was younger than Ham]. We must therefore say that she was fruitful, seven fold, over the city of Zo'an, and although there is no more stony place in the entire land of Israel than Hebron, this is the reason why it was devoted a cementery, and again there is no better land in the entire Asiatic region than that of Egypt, as it is said (Ib. 13, 10) Like the garden of the Lord, like the land of Egypt; and there is no better ground in the entire land of Egypt than that of Zo'an, as it is written (Is. 30, 4) For his princes were at Zo'an. Nevertheless Hebron was seven times as rich in fruit production as Zo'an. Is this a fact that Hebron contains stony ground? Behold it is written (II Sam. 15, 7) And it came to pass at the end of forty years, that Abshalom said unto the king, 'Let me go, I pray thee, and fulfill my vow, which I have vowed unto the Lord at Hebron; 'which was explained by R. Ivia, and according to others by Rabba b. b. Chana that this means: "He desired to go to Hebron to bring sheep for an offering." And we are also taught in a Baraitha that rams came from Moab and sheep from Hebron [hence we see that it contained pasture plains]? From the very place we can infer that it was a stony ground, and just because it was stony, therefore it was devoted to pasture ground, which fattens sheep.