The Prayer of Fear, Pursuit, Encounter, and Competition
Man Lā Yaḥḍuruh al-Faqīh|Volume 1|Book 1|Chapter 63
وَ فِي كِتَابِ عَبْدِ اَللَّهِ بْنِ اَلْمُغِيرَةِ أَنَّ اَلصَّادِقَ عَلَيْهِ اَلسَّلاَمُ قَالَ: «أَقَلُّ مَا يُجْزِي فِي حَدِّ اَلْمُسَايَفَةِ مِنَ اَلتَّكْبِيرِ تَكْبِيرَتَانِ لِكُلِّ صَلاَةٍ إِلاَّ اَلْمَغْرِبَ فَإِنَّ لَهَا ثَلاَثاً مِنَ اَلتَّكْبِيرِ.
In the book of Abdullah ibn al-Mughira, it is reported that Al-Sadiq عليه السلام said: "The minimum that suffices for the prayer during close combat (al-musayafa) is two takbirs (proclamations of 'Allahu Akbar') for each prayer, except for the Maghrib prayer, for which there are three takbirs."
- Ṣaḥīḥ al-Faqīh