Sunan of Abu Dawood Book 43, Hadith 4854

حَدَّثَنَا إِبْرَاهِيمُ بْنُ مُوسَى الرَّازِيُّ، حَدَّثَنَا مُبَشِّرٌ الْحَلَبِيُّ، عَنْ تَمَّامِ بْنِ نَجِيحٍ، عَنْ كَعْبٍ الإِيَادِيِّ، قَالَ كُنْتُ أَخْتَلِفُ إِلَى أَبِي الدَّرْدَاءِ فَقَالَ أَبُو الدَّرْدَاءِ كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم إِذَا جَلَسَ وَجَلَسْنَا حَوْلَهُ فَقَامَ فَأَرَادَ الرُّجُوعَ نَزَعَ نَعْلَيْهِ أَوْ بَعْضَ مَا يَكُونُ عَلَيْهِ فَيَعْرِفُ ذَلِكَ أَصْحَابُهُ فَيَثْبُتُونَ ‏.‏

Narrated AbudDarda': The Messenger of Allah (ﷺ) would sit and we would also sit around him. If he got up intending to return, he would take off his sandals or something he was wearing, and his Companions recognising his purpose (that he would return) would stay where they were