Pharisees come to test Jesus and to see if they can find proof that He is not the Messiah. They bring before Him the teaching of Moses on divorce. Christ indicates that Moses permitted more divorce because of the hardness of hearts of men towards their wives. We see that this law was not to do with a situation of adultery but other circumstances. It was designed to protect women who might otherwise be disgraced by the fault of their husbands.
Jesus then spells out clear teaching on the subject of divorce and remarriage. The only valid cause for divorce is immorality of one of the marriage partners. We know from other scriptures that abandonment of a believer by an unbeliever and death are also valid reasons for the cessation of the marriage covenant. In all these circumstances, when the breach in relationship proves irrevocable, divorce and remarriage are acceptable.
This teaching is applied to various categories of people in the church.