I have written about this more than once. Today I am doing so again because it is important (at least to me). In Mark 11:25 we read:
And whenever you stand praying, forgive, if you have anything against any one; so that your Father also who is in heaven may forgive you your trespasses. (RSV2CE; emphasis added)
Forgiving others is mandatory for Christians. Resentment toward them is not an option. If we do not forgive others, God will not forgive us. Hence the petition from the Our Father: “Forgive us our trespasses as we forgive those who trespass against us. Hence also the sole commentary on that prayer that Jesus offers us:
For if you forgive men their trespasses, your heavenly Father also will forgive you; but if you do not forgive men their trespasses, neither will your Father forgive your trespasses. (Matthew 6:14-15, emphasis added)
Unfortunately resentment goes right along with pride and a sense of entitlement. We think that we deserve better than what we get from someone or something, and the root of bitterness and anger and resentment starts growing in our hearts. With enough practice we get so good at it that we have difficulty stopping. We wind up feeling wronged by almost anyone whenever something fails to go the way we want, and we hold our misfortunes against others, sometimes including God.
This is death to our souls. If we do not love our neighbor, whom we can see, how will we ever love God whom we can’t see? Well, it is a rhetorical question. We can’t and don’t. Love does not mean holding a grudge. Love forgives. Love is humble. Love realizes that no one is perfect. Love knows that I am a sinner no less than that guy who just wronged me and consequently forgives him just as I hope to be forgiven. Once we have the habit it is all the harder to break it, but with the help of the grace of God and the aid of the Holy Spirit all things are possible.