13 Christ, therefore, having renewed marriage to such and so great excellence, commended and entrusted all the discipline bearing upon these matters to His Church. The Church, always and everywhere, has so used her power with reference to the marriages of Christians that men have seen clearly how it belongs to her as of native right; not being made hers by any human grant, but given divinely to her by the will of her Founder. Her constant and watchful care in guarding marriage, by the preservation of its sanctity, is so well understood as to not need proof. That the judgment of the Council of Jerusalem reprobated licentious and free love,(20) we all know; as also that the incestuous Corinthian was condemned by the authority of blessed Paul.(21) Again, in the very beginning of the Christian Church were repulsed and defeated, with the like unremitting determination, the efforts of many who aimed at the destruction of Christian marriage, such as the Gnostics, Manichaeans, and Montanists; and in our own time Mormons, St. Simonians, phalansterians, and communists.(22)
Source: Arcanum Divinae (Vatican.va)