"This is a great sacrament, but I speak in Christ and in the Church." (Ephesians 5:32)
The Protestants do not accept that marriage is a true sacrament instituted by Christ, but rather see it as pertaining to the realm of secular government. This is why Martin Luther allowed not only divorce, but even polygamy (that a man may have more than one wife).
However, the Catholic Church insists that marriage is a true sacrament of the New Law -- the "great sacrament" as St Paul calls it. We consider the institution of matrimony from the beginning when God created Adam and Eve, the first sin as a satanic assault on marriage (even as the devil will wage his last great war as a battle over marriage and the family), and how God straight away began to heal marriage. We then turn to matrimony as a Sacrament instituted by Christ - signifying and truly making present the love of Christ and of the Church.
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