Compendium of the Social Doctrine of the Church

The family has its foundation in the free choice of the spouses to unite themselves in marriage, in respect for the meaning and values of this institution that does not depend on man but on God himself: “For the good of the spouses and their offspring as well as of society, this sacred bond no longer depends on human decision alone. For God himself is the author of marriage and has endowed it with various benefits and purposes”^{473Second Vatican Ecumenical Council, Pastoral Constitution Gaudium et Spes, 48: AAS 58 (1966), 1067-1068.}. Therefore, the institution of marriage — “intimate partnership of life and love ... established by the Creator and endowed by him with its own proper laws” ^{474Second Vatican Ecumenical Council, Pastoral Constitution Gaudium et Spes, 48: AAS 58 (1966), 1067.} — is not the result of human conventions or of legislative prescriptions but acquires its stability from divine disposition^{475Cf. Catechism of the Catholic Church, 1603.}. It is an institution born, even in the eyes of society, “from the human act by which the partners mutually surrender themselves to each other”^{476Second Vatican Ecumenical Council, Pastoral Constitution Gaudium et Spes, 48: AAS 58 (1966), 1067.}, and is founded on the very nature of that conjugal love which, as a total and exclusive gift of person to person, entails a definitive commitment expressed by mutual, irrevocable and public consent^{477Cf. Catechism of the Catholic Church, 1639.}. This commitment means that the relationships among family members are marked also by a sense of justice and, therefore, by respect for mutual rights and duties.

No power can abolish the natural right to marriage or modify its traits and purpose. Marriage in fact is endowed with its own proper, innate and permanent characteristics. Notwithstanding the numerous changes that have taken place in the course of the centuries in the various cultures and in different social structures and spiritual attitudes, in every culture there exists a certain sense of the dignity of the marriage union, although this is not evident everywhere with the same clarity^{478Cf. Catechism of the Catholic Church, 1603.}. This dignity must be respected in its specific characteristics and must be safeguarded against any attempt to undermine it. Society cannot freely legislate with regard to the marriage bond by which the two spouses promise each other fidelity, assistance and acceptance of children, but it is authorized to regulate its civil effects.

The characteristic traits of marriage are: totality, by which the spouses give themselves to each other mutually in every aspect of their person, physical and spiritual; unity which makes them “one flesh” (Gen 2:24); indissolubility and fidelity which the definitive mutual giving of self requires; the fruitfulness to which this naturally opens itself^{479Cf. John Paul II, Apostolic Exhortation Familiaris Consortio, 13: AAS 74 (1982), 93-96.}. God's wise plan for marriage — a plan accessible to human reason notwithstanding the difficulties arising from “hardness of heart” (cf. Mt 19:8; Mk 10:5) — cannot be evaluated exclusively in light of the de facto behaviour and concrete situations that are at divergence with it. A radical denial of God's original plan is found in polygamy, “because it is contrary to the equal personal dignity of men and women who in matrimony give themselves with a love that is total and therefore unique and exclusive”^{480John Paul II, Apostolic Exhortation Familiaris Consortio, 19: AAS 74 (1982), 102.}.

In its “objective” truth, marriage is ordered to the procreation and education of children^{481Cf. Second Vatican Ecumenical Council, Pastoral Constitution Gaudium et Spes, 48, 50: AAS 58 (1966), 1067-1069, 1070-1072.}. The marriage union, in fact, gives fullness of life to that sincere gift of self, the fruit of which is children, who in turn are a gift for the parents, for the whole family and all of society^{482Cf. John Paul II, Letter to Families Gratissimam Sane, 11: AAS 86 (1994), 883-886.}. Nonetheless, marriage was not instituted for the sole reason of procreation^{483Cf. Second Vatican Ecumenical Council, Pastoral Constitution Gaudium et Spes, 50: AAS 58 (1966), 1070-1072.}. Its indissoluble character and its value of communion remain even when children, although greatly desired, do not arrive to complete conjugal life. In this case, the spouses “can give expression to their generosity by adopting abandoned children or performing demanding services for others”^{484Catechism of the Catholic Church, 2379.}.