Prayer During Travel
Man Lā Yaḥḍuruh al-Faqīh|Volume 1|Book 1|Chapter 59
وَ فِي رِوَايَةِ اَلْعَلاَءِ عَنْ مُحَمَّدِ بْنِ مُسْلِمٍ عَنْ أَبِي جَعْفَرٍ عَلَيْهِ اَلسَّلاَمُ قَالَ: «إِذَا صَلَّى اَلْمُسَافِرُ خَلْفَ قَوْمٍ حُضُورٍ فَلْيُتِمَّ صَلاَتَهُ رَكْعَتَيْنِ وَ يُسَلِّمُ وَ إِنْ صَلَّى مَعَهُمُ اَلظُّهْرَ فَلْيَجْعَلِ اَلْأَوَّلَتَيْنِ اَلظُّهْرَ وَ اَلْأَخِيرَتَيْنِ اَلْعَصْرَ.
In a narration from Al-‘Ala from Muhammad ibn Muslim, from Imam Muhammad ibn Ali Al-Baqir عليه السلام, He said: "If a traveler prays behind residents (those who are not traveling), he should complete his prayer as two rak'ahs and then give the salutation (end the prayer). If he prays with them at Dhuhr (noon prayer), he should make the first two rak'ahs for Dhuhr and the last two for Asr (afternoon prayer)."
- Ṣaḥīḥ al-Faqīh