In today's gospel we are given the Our Father, which if you look closely contains 7 petitions, from "hallowed be thy name" to "deliver us from evil." It's worth noting that Jesus only felt it necessary to repeat one, the one dealing with forgiveness.
Immediately after the our father we get
If you forgive men their transgressions, your heavenly Father will forgive you.
But if you do not forgive men, neither will your Father forgive your transgressions.
Every time we pray the Our Father we ask for God to offer us only limited forgiveness, to forgive us only as much as we forgive.
Is there a limit to God's forgiveness? Yes. And each one of us gets to choose our own personal limit. Every time someone wrongs us we have an opportunity to raise or lower the limit. The more we forgive the more we will be forgiven. The more we stay mad, and hold a grudge, the lower it goes.
Today if something happens, even something small, that offers you the chance to forgive, do it.