Updated: Aug 15
By Luke Lancaster
Many non-Catholic-Christians think that salvation cannot be lost. They are missing the biblical teaching of mortal sin, and in particular, the mortal sin of unforgiveness. Christians can go to hell is they refuse to forgive their neighbors. Unforgiveness is serious because of how much God puts up with man's sins. God is immensely forgiving, even when man offends him "seven times a day" (Prov. 24:16). If God forgives man his sins, then Christians necessarily have to forgive their neighbors. To refuse forgiveness severs one from Christ.
Jesus explained the nature of unforgiveness in Matthew's Gospel. After he taught his disciples how to pray the Lord’s Prayer, he expanded on it with a nugget about forgiveness. He said, "For if you forgive others their trespasses, your heavenly Father will also forgive you, but if you do not forgive others their trespasses, neither will your Father forgive your trespasses" (Mt. 6:14-15). God's forgiveness is dependent upon man's forgiveness. If a man refuses forgiveness, not even making an attempt, then it is a mortal sin.
Protestant scholar Mel Shoemaker recognized this. He commented of this idea of forgiveness with the statement, "A failure to forgive others may result in the forfeiture and loss of the Father’s forgiveness and our salvation" (The Theology of the Four Gospels, 253). Salvation can be lost through mortal sin.
It is a logical statement for Jesus to require men to forgive. God is rejected day in and day out, with only a limited number of people express sorrow. To give an image of this, God said he was like a man married to a prostitute (Hosea 1:2). God loved his people, yet his people kept finding other lovers. For God to chose to forgive men, and for men to chose to not forgive other men, is serious indeed.
Forgiveness is a process, though. Man's attempt to forgive will frequently be imperfect, but the decision clearly needs to be forgiveness. Otherwise, heaven will be lost. Christians have to be willing to pray for the person that was hurtful in some way. They need to, like Jesus, pray: “Father, forgive them; for they know not what they do” (Lk. 23:34).