Self-control is superior to conquest. Success in business, school, or home life can be ruined by a person who has lost control of his or her temper. So, it is a great personal victory to control your temper. When you feel yourself ready to explode, remember that losing control may cause you to forfeit what you want the most.
Ephesians 4:31 Get rid of all bitterness, rage, and anger, brawling and slander, along with every form of malice.
You see, not only are we to be slow to anger, but we are to put anger away from us. The spirit must rule over the body. The spirit ruled by the Lord has eternal life to look forward to.
This scripture is saying that he that is righteous is better than one who is mighty but not necessarily wise. The mighty can overtake and destroy a city or an army, but he that rules his spirit is mightier than he.