Is prayer valid if one must prostrate on muddy or wet ground?
Chapter on the Description of Prayer
Al-Mughni
Book of Prayer
Primary text
If one is encountering mud or rain such that prostration on the ground necessitates contamination by mud or water, they may pray on their riding animal, signaling the bowing and prostration. If they are walking, they should also signal the prostration, and prostrating directly on the ground is not required. This is supported by the narration from Anas ibn Malik that he prayed on his animal during water and mud, and the action of Jabir ibn Zayd and the command of Tawus and Umarah ibn Ghaziyyah. Scholars like Ishaq concur with this practice, and the established practice among people of knowledge is based on this.
Supporting text
The Companions of Shafi'i argue that an individual may not pray on a riding animal due to rain, citing the Hadith of Abu Sa'id. They assert that prostration and standing are pillars of prayer and are not waived by rain like other pillars. The preferred position is that since rain is an excuse permitting the combination of prayers (Jam'), it should affect the acts of prayer just as travel affects the shortening of prayer (Qasr).