Catechism of the Catholic Church

Thus the marriage bond has been established by God himself in such a way that a marriage concluded and consummated between baptized persons can never be dissolved. This bond, which results from the free human act of the spouses and their consummation of the marriage, is a reality, henceforth irrevocable, and gives rise to a covenant guaranteed by God's fidelity. The Church does not have the power to contravene this disposition of divine wisdom. (2365)