While some Ethiopians were playing in the presence of the Prophet, ʿUmar came in, picked up a stone and hit them with it. On that the Prophet ﷺ said, "O ʿUmar! Allow them (to play)." Maʿmar (the subnarrator) added that they were playing in the Mosque.  

بَيْنَا الْحَبَشَةُ يَلْعَبُونَ عِنْدَ النَّبِيِّ ﷺ بِحِرَابِهِمْ دَخَلَ عُمَرُ فَأَهْوَى إِلَى الْحَصَى فَحَصَبَهُمْ بِهَا فَقَالَ دَعْهُمْ يَا عُمَرُ وَزَادَ عَلِيٌّ حَدَّثَنَا عَبْدُ الرَّزَّاقِ أَخْبَرَنَا مَعْمَرٌ فِي الْمَسْجِدِ