بسم الله الرحمن الرحيم
والصلاة والسلام على رسوله الكريم
The contemporary Maliki scholar, shaykh Rami Nsour, approved the faulty position of his madhhab: “In the Maliki school it is not considered sinful to eat with the left hand” in direct contravention of the guidance of the Prophet (upon whom be peace):
لاَ تَأْكُلُوا بِالشِّمَالِ فَإِنَّ الشَّيْطَانَ يَأْكُلُ بِالشِّمَالِ
“Do not eat with the left hand, for verily Satan eats with the left hand.” (Sahih Muslim)
Salama b. AkwaRA reported 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 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. (Sahih Muslim)
So while it is apparently not “sinful” for a person to eat with his left hand according to the Maliki school, Imam Malik himself collected the following Hadith in his Muwatta:
أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم نَهَى أَنْ يَأْكُلَ الرَّجُلُ بِشِمَالِهِ
Allah’s Apostle ﷺ forbade a man eat with his left hand.
The wording of these narrations make it plain that eating with one’s left hand is not merely disliked or discouraged, but in fact strictly forbidden in the Shari’a and therefore anyone who purposely eats with his left hand is not only opposing the Prophet’s Sunna but also committing a sin. From the Sunna is to eat and drink with one’s right hand and to cleanse one’s private parts after answering the call of nature and when bathing with one’s left hand.