My reasons for finding the two accounts as complementary are simple: they have to do with the literary judgment of what kind of thing Genesis is; the sociological assessment of what role it played in ancient Israel; the textual analysis of how the material in Genesis hangs together; and then, on respect shown to later writers who refer to the passages under consideration. (The citation in Matthew & Mark, which is in fact a bringing together of the two pericopes, is part of a much larger convention of reading — one that can be found in the Hebrew Bible itself, in the mainstream Second Temple period material, and consistently in Rabbinic reflection on the passages.)