Messenger of Allah ﷺ said, "I do not take my meals while leaning (against something).  

قَالَ رَسُولُ اللَّهِ ﷺ لاَ آكُلُ مُتَّكِئًا  

While I was with the Prophet ﷺ he said to a man who was with him, "I do not take my meals while leaning."  

كُنْتُ عِنْدَ النَّبِيِّ ﷺ فَقَالَ لِرَجُلٍ عِنْدَهُ لاَ آكُلُ وَأَنَا مُتَّكِئٌ