The Sufficient (Vol 3) · Hadith 1726 (#Ḥadīth #8)
Chapter 82 | Performing Optional Salah (Prayer) on a Journey
8ـ عَلِيُّ بْنُ إِبْرَاهِيمَ عَنْ أَبِيهِ عَنِ ابْنِ أَبِي عُمَيْرٍ عَنْ عَبْدِ الرَّحْمَنِ بْنِ الْحَجَّاجِ عَنْ أَبِي عَبْدِ الله (عَلَيْهِ الْسَّلام) فِي الرَّجُلِ يُصَلِّي النَّوَافِلَ فِي الأمْصَارِ وَهُوَ عَلَى دَابَّتِهِ حَيْثُ تَوَجَّهَتْ بِهِ فَقَالَ نَعَمْ لاَ بَأْسَ.
8. Ali ibn Ibrahim has narrated from his father from ibn abu ‘ Umayr from ’Abd al- Rahman ibn al-Hajjaj who has said the following: “I once asked abu ‘Abd Allah , about a man who performs optional Salah (prayer) in the cities while on the stumper and to whatever direction it faces. He (the Imam) said, ‘Yes, it is not harmful.’”
Gradings are classical jarḥ-wa-taʿdīl, name-matched to a rijāl index (not individually re-verified).