It is narrated from Sayyiduna Abdullah bin Amir al-Thumali (may Allah be pleased with him), who was one of the Companions of the Prophet (peace and blessings be upon him), and Sayyiduna al-Hajjaj bin Amir al-Thumali (may Allah be pleased with him), who was also one of the Companions of the Prophet (peace and blessings be upon him), that they both "prayed the Fajr prayer with Sayyiduna Umar bin al-Khattab (may Allah be pleased with him), and he recited Surah al-Inshiqaq and prostrated in it."
Hadith Referenceالمعجم الكبير للطبراني / باب الحاء / 3204