CATECHISM OF THE CATHOLIC CHURCH
SECOND EDITION

Paragraphs 1622–1626

1622 "Inasmuch as it is a sacramental action of sanctification, the liturgical celebration of marriage . . . must be, per se, valid, worthy, and fruitful." It is therefore appropriate for the bride and groom to prepare themselves for the celebration of their marriage by receiving the sacrament of penance.
1623 According to Latin tradition, the spouses as ministers of Christ's grace mutually confer upon each other the sacrament of Matrimony by expressing their consent before the Church. In the tradition of the Eastern Churches, the priests (bishops or presbyters) are witnesses to the mutual consent given by the spouses, but for the validity of the sacrament their blessing is also necessary.
1624 The various liturgies abound in prayers of blessing and epiclesis asking God's grace and blessing on the new couple, especially the bride. In the epiclesis of this sacrament the spouses receive the Holy Spirit as the communion of love of Christ and the Church. The Holy Spirit is the seal of their covenant, the ever available source of their love and the strength to renew their fidelity.
1625 The parties to a marriage covenant are a baptized man and woman, free to contract marriage, who freely express their consent; "to be free" means:

- not being under constraint;

- not impeded by any natural or ecclesiastical law.

1626 The Church holds the exchange of consent between the spouses to be the indispensable element that "makes the marriage." If consent is lacking there is no marriage.