رِيَاضُ الصَّالِحِينَ
Riyad as-Salihin 745
The Book About the Etiquette of Eating
Undesirability of Eating in a Reclining Posture
عَنْ أبى جحيفة وَهْبُ بْنُ عَبْدِ اللَّهِ رضى اللَّه عَنْهُ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّه عَلَيْهِ وَسَلَّمَ: لاَ آكل مُتكئا .((رَوَاهُ البخارى))
Abu Juhaifah Wahb bin 'Abdullah (May Allah be pleased with him) reported: Messenger of Allah (ﷺ) said, "I do not eat reclining (against a pillow)." [Al-Bukhari].
Riyad as-Salihin, 745