Psalm 103:8-12 (NIV)

The LORD is compassionate and gracious, slow to anger, abounding in love.
He will not always accuse, nor will he harbor his anger forever; he does not treat us as our sins deserve or repay us according to our iniquities.  For as high as the heavens are above the earth, so great is his love for those who fear him;  as far as the east is from the west, so far has he removed our transgressions from us.

Matthew 6:9-15

“This, then, is how you should pray: “‘Our Father in heaven, hallowed be your name, your kingdom come, your will be done, on earth as it is in heaven.  Give us today our daily bread.  And forgive us our debts, as we also have forgiven our debtors. And lead us not into temptation, but deliver us from the evil one.’ For if you forgive other people when they sin against you, your heavenly Father will also forgive you. But if you do not forgive others their sins, your Father will not forgive your sins.

Ephesians 4:31-32

Let all bitterness and wrath and anger and clamor and slander be put away from you, along with all malice. Be kind to one another, tenderhearted, forgiving one another, as God in Christ forgave you. (attitude: loving and forgiving just like God forgave you)