Proverbs 16:32 He that is slow to anger is better than the mighty; and he that ruleth his spirit than he that taketh a city.
33 The lot is cast into the lap; but the whole disposing thereof is of the LORD.
Here we see it is not enough just to be slow to anger but we need to put it away completely. It does not matter how powerful someone is in conquering something, a man who is in control of his spirit is more powerful than him. This last scripture says that you can cast lots to decide a matter but if it is not how God intended then He will change the outcome to conform to His will. We all should remember that in scripture we told that we can be angry but we are not sin in our anger. Ephesians 4:31 says” Let all bitterness, and wrath, and anger, and clamour, and evil speaking, be put away from you, with all malice:”