Prayer During Travel
Man Lā Yaḥḍuruh al-Faqīh|Volume 1|Book 1|Chapter 59
وَ سَأَلَ عَمَّارٌ اَلسَّابَاطِيُّ، أَبَا عَبْدِ اَللَّهِ عَلَيْهِ اَلسَّلاَمُ: عَنْ حَدِّ اَلطِّينِ اَلَّذِي لاَ يُسْجَدُ فِيهِ مَا هُوَقَالَ «إِذَا غَرِقَتْ فِيهِ اَلْجَبْهَةُ وَ لَمْ تَثْبُتْ عَلَى اَلْأَرْضِ.
Ammar al-Sabati asked Imam Jafar ibn Muhammad Al-Sadiq عليه السلام about the extent of wetness or mud that makes it unsuitable for prostration. Imam عليه السلام said: "When the forehead sinks into it and does not remain firm on the ground”.
- Ṣaḥīḥ al-Faqīh