وَعَن ابْن عَبَّاس
قَالَ: (سَجْدَةُ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: لَيْسَ مِنْ عَزَائِمِ السُّجُودِ وَقَدْ رَأَيْتُ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يسْجد فِيهَا وَفِي رِوَايَةٍ: قَالَ مُجَاهِدٌ: قُلْتُ لِابْنِ عَبَّاسٍ: أَأَسْجُدُ فِي صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ فَقَرَأَ: (وَمِنْ ذُرِّيَّتِهِ دَاوُدَ وَسليمَان) حَتَّى أَتَى (فبهداهم اقتده) فَقَالَ: نَبِيُّكُمْ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ مِمَّنْ أَمر أَن يَقْتَدِي بهم
A prostration when reciting Sad (Al-Qur’an; 38) is not one of those which are divinely commanded, but I have seen the Prophet (sallallahu alayhi wa sallam) prostrate himself when it was recited.
In a version Mujahid said that he asked Ibn Abbas whether he should prostrate himself when reciting Sad, whereupon he recited, “And among his progeny David and Solomon. so copy the guidance they received,” (Al-Qur’an; 6:84-90) and said, “Your prophet was one of those who were commanded to copy them.”