The Catechism of St. Thomas Aquinas
Matrimony has a threefold good. The first is the birth of children and the educating of them to the worship of God. The second is that fidelity which one must render to the other; and the third is that it is a Sacrament, or, in other words, the indivisibility of Matrimony which shows forth the indivisible union of Christ and His Church.
Concerning Matrimony there are a number of errors. The first is that of Tatian, who condemned marriage, and against such it is written: “If thou take a wife, thou hast not sinned.” The second error is that of Jovinian, who made marriage equal to virginity. The third is that of the Nicolaitae, who mutually exchange their wives. There were also many other heretics who taught and worked impurities, and against which are the words of St. Paul: “Marriage honorable in all, and the bed undefiled.”
33. “This means that the consent is the effective cause of marriage, . . . because without the consent and the contract, the obligation and the bond cannot exist. . . . God Himself instituted marriage, and, as the Council of Trent declares, He made it perpetual and indissoluble. ‘What God hath joined together, let no man put asunder,’ said Our Lord (Matt., xix. 6). It belongs to marriage as a natural contract to be indissoluble; but, above all, its indissolubility arises from its nature as a Sacrament. This sacramental character raises marriage to the highest perfection. Moreover, dissolubility of marriage is immediately contrary to the proper education of children and to the other advantages of marriage. Holy Scripture frequently proposed to us the divine union of Christ and His Church under the figure of marriage” (“Roman Catechism,” “Matrimony,” 11-15).
34. Cor., vii. 28.
35. Heb., xiii. 4.