Marriage is a communion of love and life between a man and a woman.
This covenant by which a man and a woman establish between themselves a partnership of the whole of life is ordered by its nature to the goods of the spouses and the procreation and education of offspring. Jesus Christ raised this natural institution to the infinite dignity of a sacrament. Therefore, when it is celebrated between Christians it is a sacrament, an efficacious sign of the grace of God.
The intimate community of life and love which constitutes the married state has been established by the Creator and endowed by him with its own proper laws. God himself is the author of marriage. Despite the many variations it may have undergone through the centuries in different cultures, social structures and spiritual attitudes, marriage is not a purely human institution or a social construct. Although the dignity of this institution is not transparent everywhere with the same clarity, some sense of the greatness of the matrimonial union exists in all cultures. The well-being of the individual person and of both human and Christian society is closely bound up with the healthy state of conjugal and family life.
Pope Francis catechesis on the Sacrament of Marriage
Marriage is governed by Divine Law, the marriage of Catholics, however, even if only one of the parties professes the Faith of the Church, is also governed by Church law, without prejudice to the competence of civil authorities concerning the merely civil effects of marriage.
Marriage has some common and permanent characteristics. Its essential properties are unity and indissolubility. It is created by the irrevocable consent of the bride and groom legitimately manifested. Matrimonial consent is an act of the will by which one man and one woman mutually give and accept each order through a covenant to establish marriage for life. All persons who are free from coercion, grave external fear and free from impediments can marry.
There are 12 impediments to marriage according to Church Law. Some of them are of Divine Law and therefore one cannot receive a dispensation, a relaxation of Church Law. Others are of Ecclesiastical Law, thus, a person bound by them can receive a dispensation, a relaxation from Church Law, from the Holy Father, the Archbishop of Miami or the pastor of St. Patrick, depending on their nature. An impediment of Divine Law is, for example, the impediment of prior bond. If one is already validly married, nobody can authorize that person to marry again. An impediment of Church Law is, for example, a public perpetual vow of chastity. One has made a solemn and public promise that one will not marry.
Before a marriage is celebrated, it must be evident that nothing stands in the way of its valid and licit celebration, therefore, priests conduct a pre-marriage investigation to establish that the bride and the groom are free to marry, nobody is forcing them to marry against their will, and also that they are free from impediments to marriage. Couples preparing for marriage are asked to participate in programs to enrich their communications, deepen their understanding of the mystery of human love and grow in the spirituality of married life.
The celebration of marriage between two Catholic faithful normally takes place during Holy Mass, because of the connection of all the sacraments with the Paschal mystery of Christ, His Passion, Death and Resurrection. It is therefore fitting that the spouses should seal their consent to give themselves to each other through the offering of their own lives by uniting it to the offering of Christ for his Church made present in the Eucharistic sacrifice and by receiving the Eucharist so that, communicating in the same Body and the same Blood of Christ, they may form but “one body” in Christ.