The sermon centers on the radical, unconditional nature of Christian forgiveness, rooted in the believer's experience of God's infinite grace. Drawing from Matthew 18's parable of the unforgiving servant, it illustrates how the immense debt of sin forgiven by God—incalculable and unpayable—demands a corresponding response of mercy toward others, regardless of the offense. The preacher emphasizes that unforgiveness is not merely a moral failing but a spiritual indicator of whether one has truly experienced salvation, as genuine faith produces a heart that mirrors God's mercy. The message is both convicting and pastoral, challenging listeners to examine their hearts for bitterness and to recognize that refusing to forgive reveals a heart that has not fully grasped the depth of divine forgiveness. Ultimately, forgiveness is not optional but essential to the Christian life, and it is through this act that true freedom and healing are found.