From Sahih Muslim (Hadith 5268):
Salama b. Akwa' reported on the authority of his father that a person ate in the presence of Allah's Messenger (ﷺ) with his left hand, whereupon he said:Eat with your right hand. He said: I cannot do that, whereupon he (the Holy Prophet) said: May you not be able to do that. It was vanity that prevented him from doing it, and he could not raise it (the right hand) up to his mouth
Reference: Muslim 5268