EXOD358 Nothing must be done to endanger the holy alliance (Kiddushin) of man and wife. The Rabbis devote five tractates of the Talmud to this theme. Kiddushin and Ketubot deal mainly with marriage settlement; Yebamot with Levirate and prohibited marriages; Sotah with the woman suspected of adultery and Gittin with divorce, not to mention the references to these themes scattered over the other tractates. The Rabbis found it necessary to deal with these themes exhaustively in view of the vagueness of the Biblical laws. These Talmudic laws have been systematically collected into works that are still the authoritative sources of every Rabbi. These are the Mishneh Torah of Maimonides and the Eben Ha'ezer of Joseph Karo [no fewer than 178 sections dealing with marriage and divorce appear in Karo's work]. These authorities warns that intermarriage is likely to mar family purity and sew dissension and produce disreputable children [Deut. vii. 3-4; Ezra ix. 1-2, x. 10-11; Neh. x. 31, xiii. 23-25; Ab. Zara 31b; Eben Haezer xvi. 1; Maimonides Issure Biah xii.I]. Though ne Rabbinic view states that "Gentiles in the Diaspora cannot really be termed idolaters", yet marriage with them is disallowed. [Hull. 13b]. That just as virtue and righteousness flow from the worship of God, so do vice and oppression issue from the ungodly marriage, especially with daughters of the heathen. This will explain the seemingly harsh measures taken, especially by Ezra, against idolatry and immorality, both of which are to be eliminated [this verse, Lev. xix. 4; Deut iv. 15-25]. A "holy people" must remove all obstacles to the purity of family life and regard them as abominations [Deut vii.3]. Marriage is something more than a civil contract; it is an institution based on morality and implying the most sacred duties.