Hadith 1027
وَعَن ابْن عَبَّاس قَالَ: (سَجْدَةُ (ص) لَيْسَ مِنْ عَزَائِمِ السُّجُودِ وَقَدْ رَأَيْتُ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يسْجد فِيهَا
Ibn ‘Abbas said:A prostration when reciting Sad (Al-Qur’an; 38) is not one of those which are divinely commanded, but I have seen the Prophet prostrate himself when it was recited.