Anger is a somewhat controversial subject in the Christian church. Some say it is OK to get angry at someone as long as you don’t harbor it and deal with it expeditiously (don’t let the sun go down on your anger). 

Ephesians 4:26-27 “Be angry, and {yet} do not sin; do not let the sun go down on your anger, and do not give the devil an opportunity.”

Notice that the anger is not a good thing because it can open the door to demonic involvement in your life. So, you don’t want to practice it. However, the distinction here is whether you have a right to get angry at all, and if so, at whom? If this is looked at in the context of Ephesians 6:12, there would seem to be a conflict.

Ephesians 6:12 “For our struggle is not against flesh and blood, but against the rulers, against the powers, against the world forces of this darkness, against the spiritual {forces} of wickedness in the heavenly {places}.” 

We are not to struggle against people (flesh and blood) – this would include getting angry at them. This would set us against them, instead of the devil who is the real instigator. It says, for instance, that the devil accuses us day and night (Revelations 12:10), not the people standing in front of us speaking the actual words. So we should focus on Satan and not be bitter towards others.

There seems to be a righteous anger that Jesus displayed when He drove the sellers out of the temple. But in our fallen state of humanity, how many can actually walk in that kind of righteous anger without resentment, bitterness or condemnation towards the people we view as perpetrators? 

It would seem that James 1:19-20, an often quoted passage would seem to have the answer. 

James 1:19-20 “{This} you know, my beloved brethren. But let everyone be quick to hear, slow to speak {and} slow to anger; for the anger of man does not achieve the righteousness of God.” 

The reason we should be slow to anger is that we do not want to sin and come against a brother. We need to stop and realize who the real enemy is and be angry with him (the devil); we can be mad at him and even hate him. That would seem to be the righteous anger we could and should walk in – hate the devil all we want, but do not touch a brother.