Socrates believes that psychic harmony is the greatest good, and that the result of it is moral (rational) behavior. He also believes that if you have a healthy body and soul then you are in psychic harmony with yourself. He says that this is good intrinsically and instrumentally. Which means that it is good for its own sake and the sake of the consequences. Therefore, immoral behavior is a result of an unbalanced personality and leads to irrational behavior. Psychic harmony is a psychological condition and makes one moral, which according to Socrates is a social condition. Psychic harmony has no motivation. You either have it or you don't. Moral behavior comes from your own beliefs and desires. If one is bad or unjust in the social sense it is because of their sensuality, greed, or vanity. This is because of a disordered psychological condition. According to Socrates where there is "psychic harmony," the motives for injustice in the social sense will be eliminated.
I believe that Socrates is correct. If you are at peace with yourself you are also morally right towards society. Those that aren't are usually immoral and don't do what is considered right by others. I do not think it is possible to be in psychic harmony and yet act immoral. It may be possible, however, that if one is immoral, and wishes to be moral, they could learn to be in psychic harmony if they really wanted it.