9. Purity of lineage is found only among the savage
This 51 is on account of the poor life, hard conditions, and bad habitats that are peculiar to the Arabs. They are the result of necessity that destined (these conditions) for (the Arabs), in as much as their subsistence depends on camels and camel breeding and pasturage. The camels are the cause of (the Arabs') savage life in the desert, since they feed on the shrubs of the desert and give birth (to their young ones) in the desert sands, as has been mentioned before.52 The desert is a place of hardship and starvation, but to them it has become familiar and accustomed. Generations of (Arabs) grew up in the desert. Eventually, they become confirmed in their character and natural qualities. No member of any other nation was disposed to share their conditions. No member of any other race felt attracted to them. But if one of them were to find ways and means of fleeing from these conditions, he would not (do so or) give them up.53 Therefore, their pedigrees can be trusted not to have been mixed up and corrupted. They have been preserved pure in unbroken lines. This is the case, for instance, with Mudar tribes such as the Quraysh, the Kinanah, the Thaqif, the Banu Asad, the Hudhayl, and their Khuza'ah neighbors. They lived a hard life in places where there was no agriculture or animal husbandry. They lived far from the fertile fields of Syria and the 'Iraq, far from the sources of seasonings and grains. How pure have they kept their lineages! These are unmixed in every way, and are known to be unsullied.
Other Arabs lived in the hills and at the sources of fertile pastures and plentiful living. Among these Arabs were the Himyar and the Kahlan, such as the Lakhm, the Judham, the Ghassan, the Tayy, the Quda'ah, and the Iyad. Their lineages were mixed up, and their groups intermingled. It is known that people (genealogists) differ with respect to each one of these families. This came about as the result of intermixture with non-Arabs. They did not pay any attention to preserving the (purity of) lineage of their families and groups. This 54 was done only by (true) Arabs. 'Umar said: "Study genealogy, and be not like the Nabataeans of the Mesopotamian lowlands. When one of them is asked about his origin, he says: 'From such and such a village.'"55 Furthermore, the Arabs of the fertile fields were affected by the general human trend toward competition for the fat soil and the good pastures. This resulted in intermingling and much mixture of lineages. Even at the beginning of Islam, people occasionally referred to themselves by their places of residence. They referred to the Districts of Qinnasrin, of Damascus, or of the 'Awisim (the border region of northern Syria). This custom was then transferred to Spain. It happened not because the Arabs rejected genealogical considerations, but because they acquired particular places of residence after the conquest. They eventually became known by their places of residence. These became a distinguishing mark, in addition to the pedigree, used by (the Arabs) to identify themselves in the presence of their amirs. Later on, sedentary (Arabs) mixed with Persians and other non-Arabs. Purity of lineage was completely lost, and its fruit, the group feeling, was lost and rejected. The tribes, then, disappeared and were wiped out, and with them, the group feeling was wiped out. But the (earlier situation) remained unchanged among the Bedouins.
God inherits the earth and whomever is upon it.