My sense of justice is my guide.
But I think scripture provides another, more helpful, way.
Whoever covers an offense seeks love, but he who repeats a matter separates close friends (Proverbs 17:9).
Now, I am not talking about offenses that are physically harmful, recurring, or out of the ordinary. I'm talking about the day to day offenses that arise because we are sinners trying to live together in a fallen world. The mundane offenses that threaten to undo us. Your husband forgot something important (like planning a date), again. Your wife neglected you after a busy day at work, again. Your roommate went behind your back, again. Your friend talked only about herself, while failing to ask how your difficult situation was going again. All of these offenses are hurtful, sinful, and can damage a relationship. Which is what the writer of Proverbs is getting at.
Suppose your spouse or friend confesses this sin to you. They understand what they did was wrong, yet you still feel the sting of rejection and hurt. What do you do? Do you make them pay with your words? It's an easy out for me. I understand the temptation. But the writer of Proverbs gives us a better way. He tells us that repeating the sin will be the death of the relationship. And who hasn't seen that happen, right? But covering the offense is actually the loving thing to do.
So how do you "cover an offense"? Does simply saying "I forgive you" make it go away? Anyone who has ever tried reconciling knows that doesn't always cut it. Throughout scripture we are given a picture of God covering the offenses of his people. And we feel the tension of the Old Testament when God covered the offenses of the Israelites, yet they continued to go back to their sin. There needed to be a better, more complete covering, to deal with the magnitude of sin. When we are sinned against we feel it, too. I imagine that is why we feel the need to use our own words to wound. In our hurt we want the sinner to pay for what they have done to us, and in our pride we think our words will suffice.
But like the Israelites before us, there is nothing in us that will ever truly cover the offenses done against us and within us. This is why Christ had to come. Unlike the Israelites, we do have a way forward in covering the offenses of others. We live on the other side of the cross. As Paul tells us in Romans 3:25, Christ was our propitiation (our covering) for the sins we have committed (and will commit). It is only through his blood that we can truly be cleansed from our unrighteousness and covered with his righteousness.
So what does the propitiation of Christ have to do with our speech?
We can cover the offenses done against us because of the cross. The cross assures us that the sin done against us was paid for by Christ, if the offender is a believer. And if not, the cross assures us that one day Christ will come back and judge that sin on the last day. The bases regarding all sin committed against us are covered. There is nothing left for us to add to it.
This should free us in our conversations with others. When we are hurt, we can forgive because of Christ's blood and coming judgment. When we are offended, we can cover the offense because Christ has either paid for that offense or will judge it one day.
Jesus' blood is powerful enough to cleanse even the greatest offense we endure. He frees us to love, not hate when we are sinned against. He frees us to restrain our words in times of emotional crisis, and use our words for good, not evil. His blood shed for us is the means by which our speech is held back, even when our hearts tell us that our only defense is the dagger of our words. We can choose another way.