The chief rival of Christianity was Judaism, which was represented in
Northern as in Southern Arabia by strong colonies of Jews, who made
proselytes, although their strict ritualism was uncongenial to the
Arab temperament which preferred conversion to Christianity (naturally
only as a matter of form). In addition to Jewish, Christian, and Old
Semitic influences, Zoroastrian ideas and customs were also known in
Arabia, as is likely enough in view of the proximity of the Persian
empire.

These various elements aroused in Muhammed's mind a vague idea of
religion. His experience was that of the eighteenth-century
theologians who suddenly observed that Christianity was but one of
many very similar and intelligible religions, and thus inevitably
conceived the idea of a pure and natural religious system fundamental
to all others. Judaism and Christianity were the only religions which
forced themselves upon Muhammed's consciousness and with the general
characteristics of which he was acquainted. He never read any part of
the Old or New Testament: his references to Christianity show that his
knowledge of the Bible was derived from hearsay and that his
informants were not representative of the great religious sects:
Muhammed's account of Jesus and His work, as given in the Qoran, is
based upon the apocryphal accretions which grew round the Christian
doctrine.

When Muhammed proceeded to compare the great religions of the Old and
New Testaments with the superficial pietism of his own compatriots, he
was especially impressed with the seriousness of the Hebrews and
Christians which contrasted strongly with the indifference of the
heathen Arabs. The Arab was familiar with the conception of an