The Chapter of the Qibla
Man Lā Yaḥḍuruh al-Faqīh|Volume 1|Book 1|Chapter 43
وَقَالَ فِي حَدِيثٍ آخَرَ ذَكَرَهُ لَهُ: «ثُمَّ اِسْتَقْبِلِ اَلْقِبْلَةَ بِوَجْهِكَ وَ لاَ تَقَلَّبْ بِوَجْهِكَ عَنِ اَلْقِبْلَةِ فَتَفْسُدَ صَلاَتُكَ فَإِنَّ اَللَّهَ عَزَّ وَ جَلَّ يَقُولُ لِنَبِيِّهِ صَلَّى اَللَّهُ عَلَيْهِ وَ آلِهِ فِي اَلْفَرِيضَةِ «فَوَلِّ وَجْهَكَ شَطْرَ اَلْمَسْجِدِ اَلْحَرٰامِ وَ حَيْثُ مٰا كُنْتُمْ فَوَلُّوا وُجُوهَكُمْ شَطْرَهُ» فَقُمْ مُنْتَصِباً» فَإِنَّ رَسُولَ اَللَّهِ صَلَّى اَللَّهُ عَلَيْهِ وَ آلِهِ قَالَ «مَنْ لَمْ يُقِمْ صُلْبَهُ فَلاَ صَلاَةَ لَهُ وَ اِخْشَعْ بِبَصَرِكَ لِلَّهِ عَزَّ وَ جَلَّ وَ لاَ تَرْفَعْهُ إِلَى اَلسَّمَاءِ وَ لْيَكُنْ حِذَاءَ وَجْهِكَ فِي مَوْضِعِ سُجُودِكَ.
In another narration, the Imam said : "Then turn your face toward the Qiblah and do not turn your face away from the Qiblah, lest your prayer become invalid. Allah سبحانه وتعالى, the Mighty and Majestic, says to His Prophet in the obligatory prayer: 'Turn your face toward the Sacred Mosque (Surah Al-Baqarah 2:144); and wherever you are, turn your faces toward it.' Stand upright." The Prophet صلى الله عليه وعلى آله وسلم said: "Whoever does not straighten their spine (while standing) has no prayer." And lower your gaze in humility before Allah سبحانه وتعالى, the Mighty and Majestic; do not raise it to the sky. Let your gaze be directed in front of you toward your place of prostration”.
- Ṣaḥīḥ al-Faqīh