Full Sharh — Riyad as-Salihin 61
وعن سلمةَ بن الأَكْوَع أنَّ رَجُلاً أَكَلَ عِنْدَ رَسُولِ الله بِشِمَالِهِ ، فَقَالَ : « كُلْ بِيَمِينِكَ » قَالَ : لا أسْتَطِيعُ . قَالَ : « لا اسْتَطَعْتَ » ! مَا مَنَعَهُ إِلا الكِبْرُ ! فَمَا رَفَعَهَا إِلَى فِيهِ . ((رواه مسلم))
English Translation
Salamah bin Al-Akwa' (May Allah be pleased with him) reported on the authority of his father:: A man ate with his left hand in the presence of Messenger of Allah (ﷺ), whereupon he said, "Eat with your right hand." The man said: "I cannot do that." Thereupon he (the Prophet (ﷺ)) 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 afterwards..
Source
Riyad as-Salihin(رياض الصالحين)
The Book About the Etiquette of Eating
Hadith Number
61