How does that answer my question?
Muhammad built his new religion on the foundation of Judaism and Christianity.
It doesn't work that way. There are several important differences, and therefore it requires actualy reading the stuff. It's a real drag, though.
It doesn't work what way? It was a brief remark.
My assumption was that DrZoidberg was using a degree of rhetoric when he said ''I truly believe that the Bible and Koran are two fully interchangeable books'' and did not mean it to be taken literally, that the Bible and the Koran are literally interchangeable but in principle...hence my remark ''Muhammad built his new religion on the foundation of Judaism and Christianity'' - which is basically what happened. But of course it isn't the full story because Muhammad and his 'clergy' took material from a variety of sources, including medical literature from Galen. And of course, elements from his own tribal religion. But the basics are their, the prophets, Abraham, Moses, etc, culminating in Muhammad himself.
For
example:
''The theological can be subdivided into five stages: (1) Muhammad’s efforts to develop and improve on Judaism; (2) Islam’s fulfillment of Judaism; (3) Jewish resistance, based on Muhammad’s deficient knowledge of the Torah and gentile status; (4) his change in prayer direction or qiblah; and (5) Muhammad’s riposte to this resistance. The political tension and ruptures that result in warfare and conquest will be discussed afterwards, but the theological and political differences and strife parallel each other.
(1) First, while Muhammad is settling down in Medina and his position there is insecure, he tries to convince the Jews that his revelations were the continuation of Judaism (and Christianity), the religion of the People of the Book or the Bible. Before he left Mecca, he faced Syria (i.e. Jerusalem) in prayer. The early Muslims in Medina may have observed the fast for the Day of Atonement, and their special Friday worship was a response to the beginning of the Jewish Sabbath from Friday evening to Saturday evening. Muhammad forbad the Muslims from eating the same food prohibited for Jews, namely, pork, blood, carrion, and meat sacrificed to idols (see Sura 2:172-173). It seems, then, that earliest Islam was the development and even improvement on the prior faith, Judaism, or so Muhammad believed.''