From Sahih Bukhari (Hadith 6131):
Narrated Aisha:A man asked permission to see the Prophet. He said, "Let Him come in; What an evil man of the tribe he is! (Or, What an evil brother of the tribe he is). But when he entered, the Prophet (ﷺ) spoke to him gently in a polite manner. I said to him, "O Allah's Apostle! You have said what you have said, then you spoke to him in a very gentle and polite manner? The Prophet (ﷺ) said, "The worse people, in the sight of Allah are those whom the people leave (undisturbed) to save themselves from their dirty language
Reference: Bukhari 6131