The Messenger of Allah ﷺ said regarding wiping pebbles during prayer, "If you must do it, then only once."
حدثنا محمد بن الصباح وعبد الرحمن بن إبراهيم قالا حدثنا الوليد بن مسلم حدثنا الأوزاعي حدثني يحيى بن أبي كثير حدثني أبو سلمة قال
قال رسول الله ﷺ في مسح الحصى في الصلاة إن كنت فاعلا فمرة واحدة
Bukhari reported it, "Action During Prayer," chapter "Wiping Away Pebbles During Prayer," no. 1207, and Muslim, "Mosques," chapter "The Dislike of Wiping Away Pebbles and Leveling the Dust During Prayer," no. 546, from the hadith of Yahya, through this same chain.