Abu Salama reported,

I asked Abu Saeed Khudri, and he said, "I saw the Messenger of Allah ﷺ prostrating in water and mud until I saw traces of mud on his forehead."

Bukhari 836

Sahih

حدثنا مسلم بن إبراهيم قال حدثنا هشام عن يحيى

عن أبي سلمة قال

سألت أبا سعيد الخدري فقال رأيت رسول الله ﷺ يسجد في الماء والطين حتى رأيت أثر الطين في جبهته

البخاري 836صحيح
Contents
Reference
Commentary
Ayat
Collection
Sahih Bukhari
Book
Adhan
Chapter
One who did not wipe his forehead and nose until he prayed
Numbering
Darussalam 836
Bukhari 836