Halakhah su Neemia 13:78

A decree of the Court of Shem does not, however, establish a biblical prohibition. Subsequently, we find Ezra and later Nehemiah decrying intermarriage, but in neither instance do we find an explicit reference to a biblical prohibition. Nehemiah goes so far as to pronounce a curse: "In those days also saw I the Jews that had married women of Ashdod, of Ammon, and of Moab … And I contended with them and cursed them …" (Nehemiah 13:23-25). Since Nehemiah pronounces a curse upon those who behave in this manner, there is strong reason to assume that such conduct must have been banned by virtue of an explicit prohibition. The question then is: where is the scriptural locus of the prohibition concerning intermarriage?