حَدَّثَنَا سَهْلُ بْنُ تَمَّامِ بْنِ بَزِيعٍ، حَدَّثَنَا عُمَرُ بْنُ سُلَيْمٍ الْبَاهِلِيُّ، عَنْ أَبِي الْوَلِيدِ، سَأَلْتُ ابْنَ عُمَرَ عَنِ الْحَصَى الَّذِي، فِي الْمَسْجِدِ فَقَالَمُطِرْنَا ذَاتَ لَيْلَةٍ فَأَصْبَحَتِ الأَرْضُ مُبْتَلَّةً فَجَعَلَ الرَّجُلُ يَأْتِي بِالْحَصَى فِي ثَوْبِهِ فَيَبْسُطُهُ تَحْتَهُ فَلَمَّا قَضَى رَسُولُ اللَّهِ صلى الله عليه وسلم الصَّلاَةَ قَالَ ‏"‏ مَا أَحْسَنَ هَذَا ‏"

Abu al-Walid said

I asked Ibn 'Umar about the gravel in the mosque, and he said: We were rained on one night, and the earth became wet, so a man would bring gravel in his garment and spread it beneath him. When the Messenger of Allah (ﷺ) finished the prayer, he said: "How fine this is!"