Jesus really doesn't give us much wiggle room here. He tells us that we're sinning if we're angry at someone else and so we deserve God's judgment. Now—before you object—it's true that Jesus doesn't mean to condemn absolutely all anger. There are examples of Jesus being appropriately angry, and the book of Ephesians instructs Christians not to sin in our anger, which implies that anger can be justified. But it seems that appropriate anger is extremely difficult to find. When Jesus gets angry, it seems to be about others being mistreated and not about Him being upset about what's happening to Him. He never loses control of His anger, and He doesn't stay angry for long. (That same passage from Ephesians also instructs Christians not to let the sun go down while we're angry.)
I know that I often want to excuse and explain my anger. Sure, I lost my cool, but do you know what he said to me? Yes, my words were harsh, but she had been aggravating me. Maybe I was spiteful, but they ruined my dinner or undid all that work I'd done. I want to believe that what I feel is right. But Jesus demolishes my excuses. Sometimes my feelings are not just wrong but sinful. I'm responsible for my reactions and responses; I don't get to blame others for my behavior. And even if I somehow have a legitimate reason to become angry, that doesn't give me the right to stay angry. If I'm angry at someone else, I'm already starting to murder her or him in my heart. I need to turn away from my sin to God.
I don't know how we can read Jesus' words and not be convicted. I don't know how we can look inside ourselves and not find sinful anger there. We can't save ourselves. We need Jesus to forgive us. We need Jesus to transform us and help us avoid anger. Thankfully, Jesus understands our temptation to anger. He not only calls us to way of perfect righteous, but He also goes on to give us a way forward when we fail and find ourselves in the midst of anger: reconcile. He tells to let go of our anger and make peace. Jesus' words aren't easy to live out, but He teaches us the path of life, the way that He Himself lived. I don't know about you, but I need to keep on working on following Jesus, and I need to keep asking for His forgiveness and help.
Grace and peace,
BMH