(Exodus 22:20) "And a stranger you shall not afflict and you shall not oppress him": You shall not afflict him with words and you shall not oppress him in money matters. Do not say to him: "Yesterday you worshipped the deity of Nevo, and (the flesh of) swine is still between your teeth, and you would dare contend with me!" And whence is it derived that if you taunt him he can taunt you in return? From "And a stranger you shall not afflict … for you were strangers in the land of Egypt"