Narrated Abu Sa’id Al-Khudrī, “A man heard another man reciting (Sūrah Al-Ikhlāṣ) ‘Say He is Allah, (the) One.’ repeatedly. The next morning, he came to Allah’s Messenger ﷺ and informed him about it as if he thought that it was not enough to recite. On that Allah’s Messenger ﷺ said, “By Him in Whose Hand my life is, this Sūrah is equal to one-third of the Qur’an!” Reference: Sahih al-Bukhari 5013 .