Sinful anger often pretends to be righteous. Someone snubs you, criticizes you, lies about you, or harms you or someone you love, and the blood rushes to your head. And it feels justified. It feels righteous. But James 1:20 says, the wrath of man does not accomplish the righteousness of God. In Romans 12:19 it says that we must not get vengeance for ourselves but instead leave room for God to do justice: as it is written: vengeance is mine; I will repay, says the Lord. So sinful anger and wrath attempts to take the place of God: it attempts to deal out justice to those we think are wrong. But when you’re angry, you’re not thinking clearly, and you don’t really do justice. You just make everything worse. In the same place in Romans 12 it says do not be overcome by evil, but overcome evil with good. When your wife or husband says something unkind, it isn’t justice to return their harsh comment with your own biting comment. That is being overcome by evil, and it doesn’t work the righteousness of God.
Ephesians 4:26 says be angry and do not sin; do not let the sun go down on your wrath, neither give place to the devil. This means it is possible to be angry and not to sin, but it is very difficult. So God forbids taking any anger with you to bed; do not let the sun go down on it, or else the Devil will come into your house. If you go to bed angry at your husband, your wife, your parents, your kids, your roommate, your boss, your co-worker, your ex, you’re leaving your front door wide open for the Devil to come in. Many marriages and families have so much trouble because they leave the front door open for the Devil to come in every night. The way to lock the front door and keep the devil out is by getting rid of your wrath, by giving it to God and trusting Him to get justice for you, and then confessing your sinful anger to anyone you have sinned against and asking them to forgive you by the end of every day, at the very latest.