Luke 6:37

Do not judge (others self-righteously), and you will not be judged; do not condemn (others when you are guilty and unrepentant), and you will not be condemned (for your hypocrisy); pardon (others when they truly repent and change), and you will be pardoned (when you truly repent and change).

Forgiveness is enormous with God because He first forgave us.  The expectation is that as born-again believers, we walk in the steps of Jesus and love.  Forgiveness also keeps our hearts soft and our ears open to God.  It is hard to receive answered prayer with a hard, unforgiving spirit, and no believer wants it.