Al-Kāfi
Hadith 18786ـ عَلِيُّ بْنُ مُحَمَّدٍ رَفَعَهُ قَالَ قِيلَ لأَبِي عَبْدِ الله (عَلَيْهِ الْسَّلام) لِمَ صَارَ الرَّجُلُ يَنْحَرِفُ فِي الصَّلاَةِ إِلَى الْيَسَارِ فَقَالَ لأَنَّ لِلْكَعْبَةِ سِتَّةَ حُدُودٍ أَرْبَعَةٌ مِنْهَا عَنْ يَسَارِكَ وَاثْنَانِ مِنْهَا عَلَى يَمِينِكَ فَمِنْ أَجْلِ ذَلِكَ وَقَعَ التَّحْرِيفُ إِلَى الْيَسَارِ.
6. Ali ibn Muhammad has narrated in a marfu‘ manner the following: “Abu ‘Abd Allah (a.s.), was asked this question: ‘Why is man told to incline toward the left when facing the direction of Qiblah?’ He replied, ‘Ka’bah has six limits, four on the left and two on the right; for this reason inclination is toward the left.’”