From the writings of Gabriel Oussani, circa 1911
The Koran contains dogma, legends, history, fiction, religion and superstition, social and family laws, prayers, threats, liturgy, fanciful descriptions of heaven, hell, the judgment day, resurrection, etc. – a combination of fact and fancy often devoid of force and originality. The most creditable portions are those in which Jewish and Christian influences are clearly discernible. . . .
The sources of the Koran can be reduced to six:
1) The Old Testament (canonical and apocryphal) and the hybrid Judaism of the late rabbinical schools. During Mohammed’s time the Jews were numerous in many parts of Arabia, especially around Medina. Familiarity with them is undoubtly responsible for many Old Testament stories alluded to in the Koran. Later Judaism and Rabbinism are equally well represented.
2) The New Testament (canonical and apocryphal) and various heretical Christian doctrines. On his journeys between Syria, Hijaz, and Yemen, Mohammed had every opportunity to come in close touch with Yemenite, Abyssinian, Ghassanide, and Syrian Christians, especially heretic. Hence, while the influence of orthodox Christianity upon the Koran has been slight, apocryphal and heretical Christian legends, on the other hand, are one of the original sources of Koranic faith.
3) Sabaism. Sabaism was a combination of Judaism, Manicheism, and old disfigured Babylonian heathenism.
4) Zoroastrianism. On account of Persia’s political influence in the north-eastern part of Arabia, it is natural to find Zoroastrian elements in the Koran
5) Hanifism. The adherents of which, called Hanifs, must have been considerable in number and influence, as it is known from contemporary Arabian sources that twelve of Mohammed’s followers were members of this sect.
6) Native ancient and contemporary Arabian heathen beliefs and practices. Wellhausen collects in his “Reste des arabischen Heidentums” (Berlin, 1897) all that is known of pre-Islamic Arabian heathen belief, traditions, customs, and superstitions, many of which are either alluded to or accepted and incorporated in the Koran. From the various sects and creeds, and Abul-Fida, the well-known historian and geographer of the twelfth century, it is clear that religious beliefs and practices of the Arabs of Mohammed’s day form one of the many sources of Islam. From this heathen source Islam derived the practices of polygamy and slavery, which Mohammed sanctioned by adopting them.
“That in the ethics of islam there is a great deal to admire and to approve, is beyond dispute; but of originality or superiority, there is none. What is really good in Mohammedan ethics is either commonplace or borrowed from some other religions, whereas what is characteristic is nearly always imperfect or wicked.”