Three things a follower of Jesus must know about forgiveness:

We have forgiveness through Jesus Christ. “I want you to know that through Jesus the forgiveness of sins is proclaimed to you.” (Acts 13:38) God does not think about our sins when He thinks about us.
We must forgive others. Peter asks, “Lord, how many times shall I forgive my brother when he sins against me? Up to seven times!” Jesus answers, “I tell you, not seven times, but seventy times seven times.” (Matthew 18: 21-22) Scholars agree Jesus is teaching there is never a time where we should not forgive our brother or sister.
We must forgive to experience forgiveness for ourselves. “Forgive, and you will be forgiven.” (Luke 6:37)

“Therefore, as God’s chosen people, holy and dearly loved, clothe yourselves with compassion, kindness, humility, gentleness and patience. Bear with each other and forgive whatever grievances you may have against one another. Forgive as the Lord forgave you. And over all these virtues put on love, which binds them all together in perfect unity.” -Colossians 3:12-14