How do we know God's doctrine of forgiveness is true?

The truth of God's doctrine of forgiveness is firmly established in scripture. As Christians, we believe that the atonement of Christ is the foundation of our forgiveness; as articulated in 1 John 4:9-10, God demonstrated His love by sending His Son as a propitiation for our sins. This sacrificial act not only assures us of our forgiveness but also calls us to extend that forgiveness to others. Furthermore, in Matthew 6:14-15, Jesus links our forgiveness of others to the forgiveness we receive from the Father, thus affirming the theological principle that a heart transformed by grace will naturally overflow with the desire to forgive. Our assurance lies in the character of God as revealed through scripture.