Mishkat al-Masabih 4 Prayer كتاب الصلاة 421

وَعَنْ أَبِي ذَرٍّ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «إِذَا قَامَ أَحَدُكُمْ إِلَى الصَّلَاةِ فَلَا يَمْسَحِ الْحَصَى فَإِنَّ الرَّحْمَةَ تُوَاجِهُهُ» . رَوَاهُ أَحَمَدُ وَالتِّرْمِذِيُّ وَأَبُو دَاوُدَ وَالنَّسَائِيُّ وَابْنُ مَاجَه

Abu Dharr reported God’s Messenger as saying, “When one of you gets up to pray he must not remove pebbles, for mercy is facing him.”* * Meaning that such an action is unfitting when one is in God’s presence. Ahmad, Tirmidhi, Abu Dawud, Nasa’i and Ibn Majah transmitted it.