Mishkat al-Masabih 21 Foods كتاب الأطعمة 4

وَعَنِ ابْنِ عُمَرَ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «إِذَا أَكَلَ أَحَدُكُمْ فَلْيَأْكُلْ بِيَمِينِهِ وَإِذَا شَرِبَ فَلْيَشْرَبْ بِيَمِينِهِ» . رَوَاهُ مُسلم

Ibn ‘Umar reported God’s messenger as saying, “When any of you eats he should eat with his right hand, and when he drinks he should drink with his right hand.” Muslim transmitted it.