Sayyiduna Abu Hurairah (may Allah be pleased with him) narrates: The Messenger of Allah (peace and blessings be upon him) said: "People! Gather together." Then he (peace be upon him) came to us and said: "I will recite to you one third of the Qur'an." Then he (peace be upon him) recited Surah Al-Ikhlas until he completed it and did not add anything to it. Someone said: The Messenger of Allah (peace and blessings be upon him) said: "Soon I will recite to you one third of the Qur'an." He did not add anything to it, and this is news from the heavens. Then the Messenger of Allah (peace and blessings be upon him) came to us and said: "I told you that soon I would recite to you one third of the Qur'an, because Surah Al-Ikhlas is equal to one third of the Qur'an."
Hadith Referenceمسند اسحاق بن راهويه / كتاب فضائل القرآن / 573
Hadith Takhrij«مسلم ، كتاب صلاة المسافرين ، باب فضل قراء قل هو الله احد ، رقم : 812 . سنن ترمذي ، رقم : 2900 . مسند احمد : 469/2 . مسند ابي يعلي ، رقم : 6180 .»