People do not think of Islam as a heresy. However, Hilaire Bellow in The Great Heresies, stated that it was his opinion that the next great heresy the Catholic Church would have to deal with would be Islam. Indeed Islam has become a major force in the world today. Notra Aetate of Vatican II states: The Church regards with esteem also the Moslems. They adore the one God, living and subsisting in Himself; merciful and all- powerful, the Creator of heaven and earth,(5) who has spoken to men; they take pains to submit wholeheartedly to even His inscrutable decrees, just as Abraham, with whom the faith of Islam takes pleasure in linking itself, submitted to God. (Please note the reference 5 above, which refers to a letter of Pope Saint Gregory VII, alleging that it supports this decree.)
Islam appears in two forms. The Western Form is indifferent like its many cousins, liberal Protestantism, Hinduism, Buddhism and the Pog Church of Vatican II under Antipope Benedict XVI. As such it is considered an indifferent religion. Islam also has a radical form, which adheres strictly to the Koran and the admonition to destroy all infidels, and is found mainly in the Arab countries of the world, although both form are found in these countries.
The doctrine of Mahomet has caused so many evils to the Holy See, and has given it so many opportunities of displaying its constancy and its courage, that it merits especial attention here.
Mahomet, at twelve years of age, was instructed at Bosra, by a Nestorian monk, whose name, according to some Eastern authors, was Felix, son of Aba-Absabili, driven from Constantinople on account of his errors, at the time when the Nestorians had lost all credit in that city. This monk, Felix, shared the errors of the Nestorians, and he gave Mahomet his own gross idea of the Christian religion. The fatal seed germinated in the bosom of Mahomet; at first he felt horror of the idolatry in which he had been born, and that feeling being sharpened by ambition, he conceived the audacious idea of reforming religion in Arabia, and making himself master of the country.
It was to Felix that Mohomet, who could neither read nor write, owed many passages in the Koran that prove an indirect and imperfect acquaintance with the dogmas of Christianity. According to M. de Saint Martin, Felix, not to be an utter apostate, induced the impostor so far to compromise matters, as to confess Christ to be a prophet, and the son of God.
During the latter years of Mahomet’s life began that cruel war, which continued for eight hundred years, between Musselmans and the Greek empire. This war occasioned the Crusades, which cost France Saint Louis, and which, interrupted only by brief intervals, covered with its ravages Asia, Africa, and especially Italy, where the Saracens, landing in 846, advanced almost to the walls of Rome. de Montor's Lives of the Popes, volume 1, page 163
A book promoting Islam states: Muslims also believe that God revealed a holy book to Jesus called the Injeel, some parts of which may still be available in the teachings of God to Jesus in the New Testament. But this does not mean that Muslims believe in the Bible we have today because it is not the original scriptures that were revealed by God. They underwent alterations, additions, and omissions. This was also said by the Committee charged with revising The Holy Bible (Revised Standard Version). This Committee consisted of thirty-two scholars who served as members of the Committee. They secured the review and counsel of an Advisory Board of fifty representatives of the co-operating denominations. The Committee said in the Preface to The Holy Bible (Revised Standard Version), p. iv: “Sometimes it is evident that the text has suffered in transmission, but none of the versions provide a satisfactory restoration. Here we can only follow the best judgment of competent scholars as to the most probable reconstruction of the original text.” The Committee also said in the Preface, p. vii: “Notes are added which indicate the significant variations, additions, or omissions in ancient authorities (Matthew 9:34; Mark 3:16; 7:4; Luke 24:32, 51, etc.).” For more information on the altering of the Bible please visit www.islam-guide.com/bible (Providing this link does not imply endorsement of the heresies on this website!)
It was to Felix that Mahomet, who could neither read nor write, owed many passages in the Koran that prove an indirect and imperfect acquaintance with the dogmas of Christianity. de Montor's Lives of the Popes