St. John Cassian on Anger

The Philokalia, vol. I (Faber and Faber, 1979, p. 83):

If, therefore, you desire to attain perfection and rightly to pursue the spiritual way, you should make yourself a stranger to all sinful anger and wrath. Listen to what St. Paul enjoins: 'Rid yourselves of all bitterness, wrath, anger, clamour, evil speaking and all malice' (Eph. 4:31) In saying 'all' he leaves no excuse for regarding any anger as necessary or reasonable. 

[. . .]

Our incensive power can be used in a way that is according to nature only when turned against our own impassioned or self-indulgent thoughts.

We are at first told that no anger is "necessary or reasonable" and then told in effect that some anger is, namely anger at our own impassioned or self-indulgent thoughts.  

In a charitable spirit, we may take the second bit of text as correcting, rather than contradicting, the first.

There is righteous anger the object of which is oneself. I take it a step further: there is righteous anger the objects of which are others. 

But is contempt for others ever justified? I go back and forth on this question.