(a) Zirr bin Hubaysh (may Allah have mercy on him) narrates from Abdullah bin Mas'ud (may Allah be pleased with him) that he did not prostrate in Sad [Surah Sad: 1] and would say: This is only the repentance of a prophet.
(b) Abdullah bin Mas'ud (may Allah be pleased with him) did not prostrate in Sad [Surah Sad: 1].
(c) It has reached us from a large number of the Companions (may Allah be pleased with them) that they used to prostrate in Sad [Surah Sad: 1].
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 3743