Sahih al-Bukhari Book 78, Hadith 60
`Aisha said that the Jews came to the Prophet (ﷺ) and said, "As-Samu 'Alaikum" (death be on you).
`Aisha said (to them), "(Death) be on you, and may Allah curse you and shower His wrath upon you!"
The Prophet (ﷺ) said, "Be calm, O `Aisha ! You should be kind and lenient, and beware of harshness and
Fuhsh (i.e. bad words)." She said (to the Prophet), "Haven't you heard what they (Jews) have said?"
He said, "Haven't you heard what I have said (to them)? I said the same to them, and my invocation
against them will be accepted while theirs against me will be rejected (by Allah). "
Abdullah bin 'Amr mentioned Allah's Messenger (ﷺ) saying that he was neither a Fahish nor a Mutafahish. Abdullah bin 'Amr added, Allah's Messenger (ﷺ) said, 'The best among you are those who have the best manners and character.'
The Prophet (ﷺ) was not one who would abuse (others) or say obscene words, or curse (others), and if he wanted to admonish anyone of us, he used to say: "What is wrong with him, his forehead be dusted!"