Genesis 2:24

"That is why a man leaves his father and mother and clings to his wife and the two of them become one body."

"The matrimonial covenant, by which a man and a woman establish between themselves a partnership of the whole of 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."
CCC 1601

Marriage