كتاب التفسير
65  
Prophetic Commentary on the Qur'an (Tafseer of the Prophet (pbuh))
(38)
Surat Sad (Sad)
(38)
سورة ص
Sahih al-Bukhari 4806

Narrated Al-Awwam:

I asked Muhajid regarding the prostration in Surat Sa`d. He said, "Ibn `Abbas was asked the same question and he said, 'Those are they (the prophets) whom Allah had Guided. So follow their guidance." (6.90) Ibn `Abbas used to perform a prostration (on reading this Sura).

حَدَّثَنَا مُحَمَّدُ بْنُ بَشَّارٍ، حَدَّثَنَا غُنْدَرٌ، حَدَّثَنَا شُعْبَةُ، عَنِ الْعَوَّامِ، قَالَ سَأَلْتُ مُجَاهِدًا عَنِ السَّجْدَةِ، فِي ص قَالَ سُئِلَ ابْنُ عَبَّاسٍ فَقَالَ ‏{‏أُولَئِكَ الَّذِينَ هَدَى اللَّهُ فَبِهُدَاهُمُ اقْتَدِهْ‏}‏‏.‏ وَكَانَ ابْنُ عَبَّاسٍ يَسْجُدُ فِيهَا‏.‏
Reference : Sahih al-Bukhari 4806
In-book reference : Book 65, Hadith 328
USC-MSA web (English) reference : Vol. 6, Book 60, Hadith 330
  (deprecated numbering scheme)