What is indignation? It is a vindictive intention which is associated with anger when the chance to hurt is near at hand. Its function is to become the basis of taking hold of a knife, killing, and preparing to strike.It is a vindictive intention which intends to strike when any one of the nine chances for a vnidictive attitude is near at hand.-Abhidharmasamuccaya
The nine chances for a vindictive attitude are the three ideas of, "he has harmed me, he is harming me, he is going to harm me"; the three ideas of, ''he has harmed my relatives, is harming them, and is going to harm them"; and the three ideas of, "he is siding with my enemies, has sided with them, and will side with them." These nine are called the basis of harm according to the previous explanation of their causes.
In case one wonders what the difference is between anger in view of being a basic emotion [khong khro] and indignation in view of being a proximate emotion [khro ba], the answer is that anger is a vindictive mind when the above three ideas come before one's mind [dmigs yul], but indignation is an increase in anger when the chance for harming is at hand and is a very turbid state of mind leading to actual physical harm.
In explaining anger, the Abhidharmasamuccaya says that it is a vindictive attitude concerning the above three ideas and explains indignation as 'the opportunity to harm' and 'taking hold of a weapon'. The Pancaskandhaprakarana on the other hand explains anger as 'vindictiveness towards living beings', but explains indignation as the immediate act of harming. If this is what the two brothers, Asanga and Vasubandhu, have to say, intelligent people should study the problem deeply since it is very difficult to understand. The function of indignation as harming others offers no problems.