Eph. 4:26-27 And don't sin by letting anger gain control over you. Don't let the sun go down while you are still angry, for anger gives a mighty foothold to the Devil.
An angry soul makes for a miserable life. When one lives in anger, there is no longer the ability to enjoy the simple beauties of life. Anger distorts thinking to the point where no good is seen. The desire of the heart becomes revenge (and even hatred) instead of reconciliation and love. In place of mercy there is a passionate desire for vengeance. Anger controls the mind and passions of the heart and does not allow reason to be heard. An angry heart shuts God out.
It is never a good thing to allow anger to fester and grow. Living in anger destroys the capacity of heart to connect with God and others. When anger rears its ugly head, we must nip it in the bud; we must not let it take root in us beyond the moment. The longer we hold on to it, the more irrational we become and we soon becomes slaves to it. Don't let Satan have a foothold over you. Deal with whatever causes you to get angry even before the sun sets on your day.
If it is impossible to be reconciled to someone before the sun sets, be reconciled to God and deal with the wrong the next day. If you let the Lord take away the poison of your heart, you will be able to deal with the issue with reason and regain control over your life. Nothing is worth losing your soul over, and if anger is left unchecked, it can easily destroy it.
Do you have an angry heart today? Isn't it about time that you let the Lord have your anger? Tell Him what it is that is making you so angry. Tell Him what you want to see happen or do because you are angry. Tell Him how your anger is affecting your life. Confess your anger as sin, because that is what it has become. Ask the Lord to forgive you and take your anger away and give you His peace in its place. Ask Him to fill your heart with His love and give you the strength and resolve to deal with the situation positively and not negatively. If you do these things, your heart will once again be restored with God and man.
Oh, and by the way, don't be surprised if you don't want to do it. It will probably be one of the last things you want to do. But, it is what you must do if you are going to live right before God. It is obedience to God's Word and to not do it is further rebellion against God.