Marriage in the Lord
The entire Christian life bears the mark of the spousal love of Christ and the Church. Already Baptism, the entry into the People of God, is a nuptial mystery; it is so to speak the nuptial bath which precedes the wedding feast, the Eucharist. Christian marriage in its turn becomes an efficacious sign, the sacrament of the covenant of Christ and the Church. Since it signifies and communicates grace, marriage between baptized persons is a true sacrament of the New Covenant.
Source: Catechism of the Catholic Church (Vatican.va)