4 We are concerned about the whole Christian flock, as Our apostolic duties require, for We have given frequent instruction concerning the sanctity of marriage. Jesus Christ, the author of the new covenant, translated the duty of nature into sacraments, and this duty cannot be divorced from religion and immersed in worldly of fairs. Preceded by sacred rite, it can bring about a more tranquil and happy life for the spouses, strengthen family harmony, raise children more correctly, and suitably provide for the welfare of its community. Indeed, We have treated this matter in greater detail in Our apostolic letter Arcanum divinae sapientiae consilium . In that letter We wanted to remind the faithful of the vigilant cares which the Church has shown for preserving the honor and sanctity of marriage, for the Church is the best guardian and avenger of mankind. We also reminded the civil authorities of what matters they could rightfully regulate. It is not necessary for Us to bring each of these examples to your attention. It is, however, relevant to mention again that the leaders of the state have authority in human affairs which led to marriage and generally concern civil matters. However, in the truly Christian marriage, they have no authority, for this matter should be left to the jurisdiction of the Church, which is not established by men. If the marriage contract is properly performed-that is, as Christ established it - then they will be able to see if anything which pertains to civil law might follow. It is Catholic teaching that the dignity of the sacrament adds to the marriage of Christians; nobody can depart from this without losing faith. For that reason, these matters should be governed by the divine authority of the Church alone. No marriage can be considered firmly ratified unless it is joined according to Church law and discipline. It is easy to understand from this that wherever the Tridentine law of the chapter Tametsi(1) would have been correctly promulgated, then any marriage contracted against its prescription should be considered null and void. That Tridentine law was not only promulgated in Peru, but it has been enforced for a long time and faithfully observed. Therefore, the Apostolic See strongly desires to keep this teaching.
Source: Quam Religiosa (Vatican.va)