Hadith 1119
It is narrated from Sayyiduna Abu Mas’ud Ansari (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said: “Is any one of you incapable of reciting one third of the Qur’an in a single night?” The noble Companions (may Allah be pleased with them) submitted: O Messenger of Allah! Who has the strength to recite one third of the Qur’an? The Prophet (peace and blessings be upon him) said: “Is any one of you incapable of reciting «قُلْ هُوَ اللّٰهُ أَحَدٌ» (to the end of the surah)? That is, Surah Ikhlas holds the virtue equal to one third of the Qur’an.”