Jesus calls divorce and remarriage adultery, and tells us "thou shalt not commit adultery" is one of the commands we need to observe to enter into everlasting life.  Similarly, St. Paul tells us adulterers will not enter the kingdom of Heaven. Those hearing Jesus teaching on divorce and remarriage were so scandalized they said if this were true, better not to marry. 

The argument about banning divorce and remarriage being about protecting women and their economic situation is unconvincing since a man is also forbidden to marry a divorced woman, who is that place and time would need a man to support her economically.