Book 11, section 9

As you move forward in the logos, people will stand in your way. They can't keep you from doing what's healthy; don't let them stop you from putting up wiwth them either. Take care on both counts, not just sound judgments, solid actions —tolerance as well, for those who try to obstruct us or give us trouble in other ways.

Because anger, too, is weakness, as much as breaking down and giving up the struggle. Both are deserters: the man who breaks and runs, and the one who lets himself be alienated from his fellow humans.