An unforgiving heart is not a Christian's heart. Christians do not have hard hearts, they are open to hearing and obeying the Word of the Lord. The Pharisees offer a question to Christ about divorce, is it allowable for any reason? Christ explains that divorce of married couples is not in the will of God, marriage is lifelong, and that it was only permitted (not commanded) because of the hard hearts of people. We need to keep these things in mind as we look at the so called 'exception clause'.