The Prayer of Fear, Pursuit, Encounter, and Competition
Man Lā Yaḥḍuruh al-Faqīh|Volume 1|Book 1|Chapter 63
وَ قَدْ رُخِّصَ فِي صَلاَةِ اَلْخَوْفِ مِنَ اَلسَّبُعِ إِذَا خَشِيَهُ اَلرَّجُلُ عَلَى نَفْسِهِ أَنْ يُكَبِّرَ وَ لاَ يُومِئَ رَوَاهُ مُحَمَّدُ بْنُ مُسْلِمٍ عَنْ أَحَدِهِمَا عَلَيْهِمَا اَلسَّلاَمُ.
t has been permitted, in the case of the prayer of fear from a wild beast when a person fears for their life, to simply say the takbir (proclaiming "Allahu Akbar") without making gestures. This was narrated by Muhammad ibn Muslim from one of the Imams عليه السلام.
- Ṣaḥīḥ al-Faqīh