It was clear to Porphyry from his extensive firsthand knowledge that there was much of value in the Jewish scriptures, especially in some of the prophetic writings, and that they in some sense proclaimed the One High God that he too reverenced. But Porphyry was also strongly repelled by much of the Bible, particularly by its anthropomorphic images of God, its frequent anti-universalistic or even ethnocentric tendencies, and by such occasional episodes as Lot impregnating his own daughters in Genesis 19. Porphyry could not understand why the Christians did not simply reject the Jewish writings as no longer being religiously appropriate. (Sellew, "Achilles or Christ," 92; my emphasis)
I am fascinated by this dilemma. Why didn't the Christians, especially in the third and fourth centuries CE, simply cut loose of the Hebrew Bible and its traditions and pursue a more thoroughgoing New Testament theology? Why were Marcion and his followers the only ones to reject the Old Testament tout court?
I'm not advocating this move for contemporary Christianity; indeed, I find it worrisome that so much of contemporary Christianity seems to be following Marcion's lead, at least practically if not in so many words. My question (in the previous paragraph) really is, Why? I know what the Christians said: that the Bible was God's inspired word, that Moses and the prophets proclaimed Christ beforehand, etc. And these answers are themselves rooted in the general treatment of the Hebrew Bible in NT texts. But given the polemical and rhetorical energy the Church and its writers expended in its first four centuries repudiating the Jews and their reading of those texts, why did the Christians view the Jews' Bible as God's witness to the gospel's advent? Though I'm no church historian, from my NT scholar's point-of-view this seems a question too rarely raised.