A man asked permission to enter upon the Prophet. When the Prophet (ﷺ) saw
him, he said, "What an evil brother of his tribe! And what an evil son
of his tribe!" When that man sat down, the Prophet (ﷺ) behaved with him in
a nice and polite manner and was completely at ease with him. When
that person had left, 'Aisha said (to the Prophet). "O Allah's
Apostle! When you saw that man, you said so-and-so about him, then you
showed him a kind and polite behavior, and you enjoyed his company?"
Allah's Messenger (ﷺ) said, "O 'Aisha! Have you ever seen me speaking a bad
and dirty language? (Remember that) the worst people in Allah's sight
on the Day of Resurrection will be those whom the people leave
(undisturbed) to be away from their evil (deeds)."
Sahih al-Bukhari Book 78, Hadith 62