Hadithcore
Mishkat al-Masabih, 4240

He reported God’s messenger as saying, "When food is set down take off your sandals, for it gives more rest to your feet."

وَعَنْهُ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «إِذَا وُضِعَ الطَّعَامُ فَاخْلَعُوا نِعَالَكُمْ فإِنَّه أرْوَحُ لأقدامكم»

References1 variant
In-Book Reference
Book 21, Hadith 77