Christ was grieved when the forgiven Simon neglected to show his gratitude by words and deeds of love. These words can be misinterpreted, as if to say that God's forgiveness depends on ours. In other words, if we are unforgiving, we cut off the very channel through which we receive mercy from God. The merciful love of God that we receive must flow through us to others in a spirit of compassion. Jesus taught this lesson in His parable of the unmerciful servant, telling us never to become tired of forgiving those who ask us for forgiveness.
Nothing can justify an unforgiving spirit.
He who is unmerciful toward others shows that he himself is not a partaker of God's pardoning grace. . . . He has separated himself from God, and is in the same condition as before he was forgiven. Sometimes we set a limit to our forgiveness of others, like three times or even seven times. God's forgiving mercy must be the measure of our forgiveness of others. Divine forgiveness is and remains God's prerogative and sovereign possession, even after we have received it.