Man Lā Yaḥḍuruh al-Faqīh

Hadith 1258
travel-prayer
1266 - وَ سَأَلَ مُحَمَّدُ بْنُ مُسْلِمٍ أَبَا عَبْدِ اَللَّهِ عَلَيْهِ اَلسَّلاَمُ فَقَالَ لَهُ: اَلرَّجُلُ يُرِيدُ اَلسَّفَرَ مَتَى يُقَصِّرُ قَالَ «إِذَا تَوَارَى مِنَ اَلْبُيُوتِ» قَالَ قُلْتُ لَهُ اَلرَّجُلُ يُرِيدُ اَلسَّفَرَ فَيَخْرُجُ حِينَ تَزُولُ اَلشَّمْسُ فَقَالَ «إِذَا خَرَجْتَ فَصَلِّ رَكْعَتَيْنِ.
Hadith.1266 - Muhammad ibn Muslim asked Abu Abdullah (as) about when a person who intends to travel should begin shortening their prayers. He (as) replied: "When he is no longer within sight of the houses." Muhammad then said: "If a person intends to travel and leaves at the time of the sun's decline (midday), what should he do?" He (as) replied: "When you leave, pray two units (Rak'ahs)."
Source: Shaykh Muḥammad b. ʿAlī al-Ṣaduq