The discrimination between good and evil is in man's soul. Every man can judge that for himself, because in every man is the sense of admiration of beauty. Happiness only lies in thinking or doing that which one considers beautiful. Such an act becomes a virtue or goodness.
Hazrat Inayat KhanIn Sufi terms the crushing of the ego is called Nafs Kushi. And how do we crush it? We crush it by sometimes taking ourselves to task. When the self says, 'O no, I must not be treated like this,' then we say, 'What does it matter?' When the self says, 'He ought to have done this, she ought to have said that,' we say, 'What does it matter, either this way or that way? Every person is what he is; you cannot change him, but you can change yourself.' That is the crushing. ... It is only in this way that we can crush our ego.
Hazrat Inayat Khan