I was never good at changing dirty diapers. My wife, Debbie, changed many more diapers than I ever did with our three girls. Whether it was a weak stomach or a strong sense of smell, or just a selfish aversion to the task, I had trouble with dirty diapers. When there was no other way out and I had to do it, I’d wrap a towel around my face just to be able to handle the odor. And then, after I got that soiled diaper off the baby, I disposed of it as fast as I could. No one wants to linger in the presence of a dirty diaper.

When it comes to an unforgiving, bitter heart, understand this: Holding on to past hurts is like clinging to a dirty diaper. Refusing to forgive someone who hurt you is just like taking a soiled diaper and, instead of throwing it away, tucking it away in your breast pocket … and carrying it with you everywhere you go. That’s exactly what we do when we won’t forgive those who have hurt us, whether accidentally or intentionally. We take all that hurt and all that dirt and filth and bring it into our hearts, and we say, “I’m hanging on to this.” The irony, of course, is we imagine that by holding on to the dirty diaper, we will somehow hurt the person who has hurt us. How foolish.

Someone once said that unforgiveness is like drinking poison and thinking it will kill the person who hurt you. But it never hurts him; it just hurts you. If you drink the poison, then you will be poisoned … and your offender will go on enjoying his life.

God says you need to forgive, and that’s how you get rid of all that anger churning around inside you. You forgive the father who hurt you … the child who betrayed you … the employer who used and then discarded you … the business partner who cheated you … the spouse who divorced you … the friend who demeaned you. You let it go.

How do you do that? Maybe it will be a little like Peter’s experience in Matthew 14, when he crawled over the edge of the boat on that stormy night, and put his foot on the water. He had certainly never walked on water in his whole life until that moment, and really had no idea how he was going to do it this time. But Jesus had said, “Come,” so Peter stepped over the edge and did the impossible. And that first step was probably the most frightening one of all.

Even though you may not feel like doing this—even though it may seem as difficult as stepping over the side of a boat on a wild, windswept night—you must say, “God, I need You, and I affirm that at this very moment, I forgive the person who hurt me. Father, You deal with him [or her], and please let Your transforming grace flow through my heart right now.”

In Romans 12, Paul wrote: “Never pay back evil with more evil … Do all that you can to live in peace with everyone. Dear friends, never take revenge. Leave that to the righteous anger of God. For the Scriptures say, ‘I will take revenge; I will pay them back,’ says the Lord” (verses 17-19, NLT).

People who refuse to forgive those who have harmed them must deal with the Lord’s strong, sobering words in Matthew 6:14-15: “If you forgive others for their transgressions, your heavenly Father will also forgive you. But if you do not forgive others, then your Father will not forgive your transgressions.”

Wow. Did you catch that? If you won’t forgive those who hurt you, He won’t forgive you.

Someone once told a famous preacher of yesteryear, “I cannot forgive this man for what he did to me.” And that preacher wisely replied, “Well then, I suggest you never sin again, because God won’t forgive you if you won’t forgive that man.”

Maybe that’s where you are today. Perhaps you are holding on to a memory of something someone did to you or said to you five years ago—or 10, or 20, or 50 years ago. You’ve clung to the dirty diaper of unforgiveness all this time, and it’s become toxic to your system. We fool ourselves if we claim that we have a walk with the Lord while still holding on to bitterness and hatred in our hearts. How can we be in fellowship with God when He has told us clearly that He won’t forgive our sins unless we forgive the sins of others against us?*

Be honest here. Are you having difficulty forgiving? Then remember how often you have offended God, and how much He has forgiven you. You’ve hurt Him countless times more than anybody could have ever hurt you. You’ve sinned against God over and over (and over and over …) again, and so have I. But God has forgiven us by His grace … and that grace enables us to forgive others.

*Editor’s note: This Scripture does not tell us that we will lose our salvation if we do not forgive others.  Instead, it speaks of a believer’s daily walk with God, and the fact that unconfessed sin will short-circuit our relationship with Him.  See 1 John 1:5-10.

Excerpted from Runaway Emotions, Copyright ©2013 by Jeffrey B. Schreve. Used with permission from Thomas Nelson.