The Prophet ﷺ said, "When one of you stands for prayer, mercy faces him, so let him not wipe away the pebbles."In another narration, "Let him not touch the pebbles."
عن النبي ﷺ: إذا قام أحدكم إلى الصلاة، فإن الرحمة تواجهه، فلا يمسح الحصى وفي رواية: فلا يمس الحصى
Abu Dawud (945), Tirmidhi (379), Nasai (1190), Ibn Majah (1027), and Ahmad (21330) all reported it through various routes from Sufyan, from Zuhri, from Abu Ahwas, a shaykh from the people of Madinah, from Abu Dharr, who then related it. The wording given is that of Abu Dawud. Tirmidhi said, "Hasan." Ibn Khuzayma (914, 913), Ibn Hibban (2273, 2274), and Hakim (1/236) all graded it sahih, all of them through this same route. Its chain is hasan because of Abu Ahwas.