From these fugitives sprang three Jewish-Arabic tribes—the Benu-Nadhir, the Benu-Kuraiza, and the Benu-Bachdal, the first two of which were descended from Aaron, and therefore called themselves Cohanim (Al-kahinani). Another Jewish family—the Benu-Kainukaa—were established in northern Arabia, and their mode of living was different from that of the Nadhir and Kuraiza. These tribes had their center in the city of Yathrib, which was situated in a fruitful district, planted with palms and rice, and watered by small streams. As the Jews were often molested by Bedouins, they built castles on the elevated places in the city and the surrounding country, whereby they guarded their independence. Although originally the sole rulers of this district, they were afterwards obliged to share their power and the possession of the soil with the Arabs, for, about the year 300, two related families, the Benu-Aus and the Chazraj (together forming the tribe of Kaila), settled in the same neighborhood, and sometimes stood in friendly, sometimes in hostile relations to the Jews.

To the north of Yathrib was situated the district of Chaibar, which was entirely inhabited by Jews, who constituted a separate commonwealth. The Jews of Chaibar are supposed to have been descendants of the Rechabites, who, in accordance with the command of their progenitor, Jonadab, the son of Rechab, led a nomadic and Nazarite life; after the destruction of the First Temple, they are said to have wandered as far as the district of Chaibar, attracted by its abundance of palms and grain. The Jews of Chaibar constructed a line of castles or fortresses, like the castles of the Christian knights; the strongest of them was Kamus, built upon a hill difficult of access. These castles protected them from the predatory incursions of the warlike Bedouins, and enabled them to offer an asylum to many a persecuted fugitive. Wadil-Kora (the valley of the villages), a fertile plain a day's journey from Chaibar, was also inhabited exclusively by Jews. In Mecca, where stood the sanctuary of the Arabs, there probably lived but few Jews.

They were numerously represented, however, in southern Arabia (Yemen), "the land," its inhabitants boasted, "the very dust of which was gold, which produced the healthiest men, and whose women brought forth without pain." But unlike their brethren in Hejas, the Jews of Arabia Felix lived without racial or political cohesion, scattered among the Arabs. They nevertheless in time obtained so great an influence over the Arab tribes and the kings of Yemen (Himyara), that they were able to prevent the propagation of Christianity in this region. The Byzantine Christian emperors had their desires fixed upon these markets for Indian produce. Without actually meditating the subjection of the brave Himyarites (Homerites), they desired to gain their friendship by converting them to Christianity; the cross was to be the means of effecting a commercial connection. It was not until the end of the fifth or the beginning of the sixth century that the Christian envoys succeeded in converting to Christianity an Arab prince and his tribe, whose capital was the commercial town of Najara.—Arabia owned only half the island of Yotabe (now Jijbân), in the Red Sea (60 miles to the south of the capital, Aila); a small Jewish free state had existed there since time immemorial.

In consequence of their Semitic descent, the Jews of Arabia possessed many points of similarity with the primitive inhabitants of the country. Their language was closely related to Arabic, and their customs, except those that had been produced by their religion, were not different from those of the sons of Arabia. The Jews became, therefore, so thoroughly Arabic that they were distinguished from the natives of the country only by their religious belief. Intermarriage between the two nations tended to heighten the similarity of their characters. Like the Himyarites, the Jews of southern Arabia applied themselves more particularly to the trade between India, the Byzantine empire, and Persia. The Jews of northern Arabia, on the contrary, led the life of Bedouins; they occupied themselves with agriculture, cattle breeding, transport by caravan, traffic in weapons, and probably also the calling of robbers. The Arabian Jews likewise possessed a patriarchal, tribal constitution. Several families were united under one name, and led by a chieftain (shaïch), who in times of peace settled controversies and pronounced judgment, and in war commanded all the men able to bear arms, and concluded alliances with neighboring tribes. Like the Arabs, the Jews of the peninsula extended their hospitality to every one who entered their tents, and held inviolable faith with their allies; but they shared also the faults of the original inhabitants of the peninsula, avenging the death of one of their number with rigorous inflexibility, and hiding in ambush in order to surprise and annihilate their enemy. It would sometimes happen that a Jewish tribe, having entered into an alliance with an Arabian clan, would find itself opposed to a kindred tribe which had espoused another cause. But even though Jews were at feud with each other, their innate qualities moderated in them Bedouin ferocity, which never extended mercy to a foe. They ransomed the prisoners of a kindred tribe with which they happened to be at war, from the hands of their own allies, being unwilling to abandon them as slaves to heathens, "because," said they, "the redemption of such of our co-religionists as are prisoners is a religious duty." Besides being equal to the Arabs in bravery, the Jews also contended with them for the palm in poetry. For in addition to manliness and courage, poetry was cultivated among the Arab nobles; it was fostered by the chieftains, and richly rewarded by the Arab kings. Next to the warrior, the poet was the man most honored in Arabia; for him all hearts and tents opened wide. The Jews of Arabia were likewise able to speak with elegance the Arabic language, and to adorn their poetry with rhymes.

The knowledge of their religion, which the Arabian Jews had brought with them in their flight from Judæa, and that which afterwards came to them from the academies, conferred upon them superiority over the heathen tribes, and soon made them their masters. While but few Arabs, before the latter part of the seventh century, were familiar with the art of writing, it was universally understood by the Jews, who made use, however, of the square, the so-called Assyrian characters. As the few Arabs that succeeded in learning to write generally employed the Hebrew characters, it would appear that they first acquired the art of writing from the Jews. Every Jew in Arabia was probably able to read the Holy Scriptures, for which reason the Arabs called the Jews the "nation of writing" (Ahl' ul kitab).

In the form in which it was transmitted to them, that is to say, with the character impressed upon it by the Tanaim and the Amoraim, Judaism was most holy to the Arabian Jews. They strictly observed the dietary laws, and solemnized the festivals, and the fast of Yom-Kippur, which they called Ashura. They celebrated the Sabbath with such rigor that in spite of their delight in war, and the opportunity for enjoying it, their sword remained in its scabbard on that day. Although they had nothing to complain of in this hospitable country, which they were able to regard and love as their fatherland, they yearned nevertheless to return to the holy land of their fathers, and daily awaited the coming of the Messiah. Like all the Jews of the globe, therefore, they turned their face in prayer towards Jerusalem. They were in communication with the Jews of Palestine, and even after the fall of the Patriarchate, willingly subordinated themselves to the authorities in Tiberias, whence they received, as also from the Babylonian academies probably, religious instruction and interpretation of the Bible. Yathrib was the seat of Jewish learning, and possessed teachers of the Law (Achbâr, Chabar) who expounded the Scriptures in an academy (Midras). But the knowledge of the Bible which the Arabian Jews possessed was not considerable. They were acquainted with it only through the medium of the Agadic exegesis, which had become familiar to them in their travels or had been brought to them by immigrants. For them the glorious history of the past coalesced so completely with the Agadic additions that they were no longer able to separate the gold from the dross. Endowed with poetical fancy, the Arabian Jews on their side embellished the Biblical history with interesting legends, which were afterwards circulated as actual facts.

The Jews of Arabia, enjoying complete liberty, and being subjected to no restraint, were able to defend their religious opinions without fear, and to communicate them with impunity to their heathen neighbors. The Arab mind, susceptible to intellectual promptings, was delighted with the simple, sublime contents of the Bible, and by degrees certain Jewish conceptions and religious ideas became familiar and current in Arabia. The Arabian Jews made their neighbors acquainted with a calendar-system, without which the latter were completely at sea in the arrangement of their holy seasons; learned Jews from Yathrib taught the Arabs to insert another month in their lunar year, which was far in arrear of the solar year. The Arabs adopted the nineteen-years cycle of the Jews (about 420), and called the intercalary month Nasi, doubtless from the circumstance that the Jews were accustomed to receive their calendar for the festivals from their Nasi (Patriarch).

The Jews even succeeded in instructing the Arabs in regard to their historical origin, concerning which their memories were void, and in their credulity the latter accepted this genealogy as the true one. It was of great consequence to the Jews to be regarded and acknowledged by the Arabs as their kinsmen, and too many points of social interest were bound up with this relationship for them to allow it to escape their attention. The holy city of Mecca (Alcharam), the chief city of the country, was built round an ancient temple (Kaaba, the Square), or more properly, round a black stone; for all Arabs it was an asylum, in which the sword durst not quit the sheath. The five fairs, the most important of which was at Okaz, could be frequented only in the four holy months of the year, when the truce of God prevailed. Whoever desired to take advantage of these periods and to enjoy security of life in the midst of a warlike people, not over-scrupulous in the matter of shedding blood, was obliged to establish his relationship to the Arabs, otherwise he was excluded from these privileges.

Happily, the Arabian Jews bethought them of the genealogy of the Arabs as set forth in the first book of the Pentateuch, and seized upon it as the instrument by which to prove their kinship with them. The Jews were convinced that they were related to the Arabs on two sides, through Yoktan and through Ishmael. Under their instruction, therefore, the two principal Arabian tribes traced back the line of their ancestors to these two progenitors, the real Arabs (the Himyarites) supposing themselves to be descended from Yoktan; the pseudo-Arabs in the north, on the other hand, deriving their origin from Ishmael. These points of contact granted, the Jews had ample opportunity to multiply the proofs of their relationship. The Arabs loved genealogical tables, and were delighted to be able to follow their descent and history so far into hoary antiquity; accordingly, all this appeared to them both evident and flattering. They consequently exerted themselves to bring their genealogical records and traditions into unison with the Biblical accounts. Although their traditions extended over less than six centuries on the one side to their progenitor Yarob and his sons or grandsons Himyar and Kachtan, and on the other, to Adnan, yet in their utter disregard of historical accuracy, this fact constituted no obstacle. Without a scruple, the southern Arabians called themselves Kachtanites, and the northern Arabians Ishmaelites. They readily accorded to the Jews the rights of relationship, that is to say, equality and all the advantages attending it.

The Arabs were thus in intimate intercourse with the Jews, and the sons of the desert, whose unpoetical mythology afforded them no matter for inspiration, derived much instruction from Judaism. Under these circumstances many Arabs could not fail to develop peculiar affection for Judaism, and some embraced this religion, though their conversion had not been thought of by the Jews. As they had practised circumcision while heathen, their conversion to Judaism was particularly easy. The members of a family among the Arabs were indissolubly bound to one another, and, according to their phylarchic constitution, the individuals identified themselves with the tribe. This brought about, that when a chieftain became a Jew, his whole clan at once followed him, the wisest, into the fold of Judaism. It is expressly recorded about several Arabian tribes that they were converted to Judaism; such were the Benu-Kinanah, a warlike, quarrelsome clan, related to the most respected Koraishites of Mecca, and several other families of the tribes Aus and Chazraj in Yathrib.