Essay on Plato’s apology 400 слов

Using Plato's Apology of Socrates (and particular the below passage), why is "engaging in discourse every day about excellence" the highest good for man? Wouldn't actually being excellent be the highest good for man?
Socrates: "Now, someone might perhaps say, “Socrates, if you kept quiet and lived a quiet life, wouldn’t you be able to live on, once we had cast you out?” The most difficult thing of all is to convince some of you on this issue, for if I say that this would constitute disobedience to the god and that is why I cannot hold my peace, you do not believe me as you think I am not in earnest (i.e., ironic). And if I also go on to say the highest good for a man is to engage in discourse every day about excellence, and the other issues on which you have heard me discoursing, and examining myself and others, and that for a human being an unexamined life is not worth living, you are even less convinced by what I say."