The Chapter of the Qibla
Man Lā Yaḥḍuruh al-Faqīh|Volume 1|Book 1|Chapter 43
وَقَالَ رَجُلٌ لِلصَّادِقِ عَلَيْهِ اَلسَّلاَمُ: إِنِّي أَكُونُ فِي اَلسَّفَرِ وَ لاَ أَهْتَدِي إِلَى اَلْقِبْلَةِ بِاللَّيْلِ فَقَالَ «أَ تَعْرِفُ اَلْكَوْكَبَ اَلَّذِي يُقَالُ لَهُ اَلْجَدْيَ» قُلْتُ نَعَمْ قَالَ «فَاجْعَلْهُ عَلَى يَمِينِكَ وَ إِذَا كُنْتَ عَلَى طَرِيقِ اَلْحَجِّ فَاجْعَلْهُ بَيْنَ كَتِفَيْكَ.
A man said to Imam Al-Sadiq عليه السلام: "I am sometimes traveling and cannot determine the Qiblah at night." The Imam asked: "Do you know the star that is called 'al-Jady' (the North Star)?" The man replied: "Yes." The Imam said: "Place it to your right, and if you are on the pilgrimage route, place it between your shoulders”.
- Ṣaḥīḥ al-Faqīh, p. 43