Can. 1055 - §1. The matrimonial covenant, by which a man and a woman establish between themselves a partnership of a whole life, is by its nature ordered toward the good of the spouses and the procreation and education of offspring; this covenant between baptized persons has been raised by Christ the Lord to the dignity of a sacrament.
§2. For this reason a matrimonial contract cannot validly exist between baptized persons unless it is also a sacrament by that fact.
Can. 1056 - The essential properties of marriage are unity and indissolubility, which in Christian marriage obtain a special firmness in virtue of the sacrament.
Can. 1057 - §1. Marriage is brought about through the consent of the parties, legitimately manifested between persons who are capable according to law of giving consent; no human power can replace this consent.
§2. Matrimonial consent is an act of the will by which a man and a woman, through an irrevocable covenant, mutually give and accept each other in order to establish marriage.
Can. 1058 - All persons who are not prohibited by law can contract marriage.
Can. 1059 - Even if only one party is baptized, the marriage of Catholics is regulated not only by divine law but also by canon law, with due regard for the competence of civil authority concerning the merely civil effects of such a marriage.
Can. 1066 - Before marriage is celebrated, it must be evident that nothing stands in the way of its valid and licit celebration.
Can. 1096 - §1. For matrimonial consent to be valid it is necessary that the contracting parties at least not be ignorant that marriage is a permanent consortium between a man and a woman which is ordered toward the procreation of offspring by means of some sexual cooperation.
Can. 1108 - §1. Only those marriages are valid which are contracted in the presence of the local ordinary or the pastor or a priest or deacon delegated by either of them, who assist and in the presence of two witnesses...
§2. The one assisting at a marriage is understood to be only that person who, present at the ceremony, asks for the contractants' manifestation of consent and receives it in the name of the Church.