alkafi-4617Vol. 3, p. 215
سَأَلْتُ الرِّضَا ع عَنِ الْمَصْلُوبِ فَقَالَ أَ مَا عَلِمْتَ أَنَّ جَدِّي ع صَلَّى عَلَى عَمِّهِ[2] قُلْتُ أَعْلَمُ ذَاكَ وَ لَكِنِّي لَا أَفْهَمُهُ مُبَيَّناً قَالَ أُبَيِّنُهُ لَكَ إِنْ كَانَ وَجْهُ الْمَصْلُوبِ إِلَى الْقِبْلَةِ فَقُمْ عَلَى مَنْكِبِهِ الْأَيْمَنِ وَ إِنْ كَانَ قَفَاهُ إِلَى الْقِبْلَةِ فَقُمْ عَلَى مَنْكِبِهِ الْأَيْسَرِ فَإِنَّ بَيْنَ الْمَشْرِقِ وَ الْمَغْرِبِ قِبْلَةً وَ إِنْ كَانَ مَنْكِبُه
‘Do you not know that my grandfather performed Salah (prayer) for his uncle?’ I said, ‘I know it but I do not understand it clearly.’ He (the Imam) said, ‘I explain it for you. If the face of the person crucified is toward al-Qiblah (al-Ka‘bah), stand near his right shoulder. If his back is toward al-Qiblah (al-Ka‘bah)