John Chrysostom (attributed)

But as none is empty who has the Holy Spirit, so none is a fool who has the knowledge of Christ; and if Racha signifies ‘empty,’ it is one and the same thing, as far as the meaning of the word goes, to say Racha, or ‘thou fool.’ But there is a difference in the meaning of the speaker; for Racha was a word in common use among the Jews, not expressing wrath or hate, but rather in a light careless way expressing confident familiarity, not anger. But you will perhaps say, if Racha is not an expression of wrath, how is it then a sin? Because it is said for contention, not for edification; and if we ought not to speak even good words but for the sake of edification, how much more not such as are in themselves bad?