Collins himself was not put to silence. Besides other writings of minor importance, he published in 1724 the most weighty of all his works, a ‘Discourse on the Grounds and Reasons of the Christian Religion.’ The object of this book is to show that Christianity is entirely founded on the fulfilment of the Old Testament prophecies, and then to prove that these prophecies were fulfilled not in a literal, but only in a typical or secondary sense. Novelty, he argues, is a weighty reproach against any religious institution; the truth of Christianity must depend upon the old dispensation; it is founded on Judaism. Jesus makes claim to obedience only so far as He is the Messias of the Old Testament; the fundamental article of Christianity is that Jesus of Nazareth is the Jewish Messiah, and this can only be known out of the Old Testament. In fact, the Old Testament is the only canon of Christians; for the New Testament is not a law book for the ruling of the Church. The Apostles rest their proof of Christianity only on the Old Testament. If this proof is valid, Christianity is strong and built upon its true grounds; if weak, Christianity is false. For no miracles, no authority of the New Testament can prove its truth; miracles can only be a proof so far as they are comprehended in and exactly consonant with the prophecies concerning the Messias. It is only in this sense that Jesus appeals to His miracles. Christianity, in a word, is simply the allegorical sense of the Old Testament, and therefore may be rightly called ’Mystical Judaism.’
As all this bore the appearance of explaining away Christianity altogether, or at least of making it rest upon the most shadowy and unsubstantial grounds, there is no wonder that it called forth a vehement opposition: no less than thirty-five answerers appeared within two years of its publication, among whom are found the great names of T. Sherlock, Zachary Pearce, S. Clarke, and Dr. Chandler. The latter wrote the most solid and profound, if not the most brilliant work which the Deistical controversy had yet called forth.