"..let me return to the term "abomination" and the history of it's use by Jews as a means of referring ... to the cross. The earliest instance I have been able to find occurs in the late midrashic work known as Pirkei de-Rabbi Eliezer (The Chapters of Rabbi Eliezer), which, as noted earlier, was evidently composed in eighth century Palestine. As we have seen, the work's author implicitly attempts, in retelling the story of Purim, to solve one of the thorniest problems in the exegesis of the book of Esther: Why did Mordecai refuse to bow down to Haman? According to Pirkei de-Rabbi Eliezer, Haman "had an 'image' [tzelem] embroidered on his garment, and anyone who bowed down to Haman bowed also to the 'abomination' [to'eva] which he had made. Mordecai saw this and did not consent to bow down to his 'disgusting thing' [shikutzo], as it is said, 'But Mordecai bowed not, nor did him reverence.'" The author of this late midrash transforms Haman into a Christian bishop who proudly wears upon his chest the sign of the cross, referred to by the uncomplimentary trinity of Hebrew terms--tzelem [image], to'eva [abomination], shikutz [disgusting]. And although the midrashic author apparently resided in Umayyad Palestine, he nonetheless felt the need to link the ancient arch-enemy of the Jewish people with the central symbol of Christianity.
This is actually less anomalous than it might first appear ... (Reckless Rites, pp.157-158, Elliot Horowitz, Princeton University Press)
This puts the ... abominable notions, "Judeo-Christian tradition" and "elder brothers in the faith" in a rather clearer perspective, does it not?