An elder from among the people of Medina reported that he heard Abu Dharr narrating from the Prophet ﷺ who said, "When one of you stands for prayer, mercy faces him, so let him not wipe away the pebbles."
حدثنا مسدد حدثنا سفيان عن الزهري
شيخ من أهل المدينة أنه سمع أبا ذر يرويه عن النبي ﷺ قال إذا قام أحدكم إلى الصلاة فإن الرحمة تواجهه فلا يمسح الحصى
[Hasan] Reported by Tirmidhi, in the Book of Prayer, chapter on the dislike of wiping away pebbles during prayer, no. 379, and Nasai, no. 1192, and Ibn Majah, no. 1027, from the hadith of Sufyan through this chain. Tirmidhi graded it hasan, and Ibn Khuzayma graded it sahih, no. 913, 914, as did Ibn Hibban, no. 481, 482, and Hafiz in Bulugh Maram, no. 189. The hadith has corroborating narrations.