Sayyiduna Abu Salamah (may Allah be pleased with him) said: I saw Sayyiduna Abu Hurairah (may Allah be pleased with him) prostrating in «إِذَاالسَّمَاءُانْشَقَّتْ»[سورة الانشقاق], so it was said to him: "You prostrate in this Surah in which prostration was not done." He replied: "I saw the Messenger of Allah (peace and blessings be upon him) prostrating in it."
Hadith Referenceسنن دارمي / من كتاب الصللاة / 1507