Narrated by Sayyiduna Abu Sa'id Al-Khudri (may Allah be pleased with him):
A man heard someone reciting "(Qul Huwa Allahu Ahad)" (Surah Al-Ikhlas) repeatedly. In the morning, he came to the Messenger of Allah (peace and blessings be upon him) and mentioned this, as if he considered "(Qul Huwa Allahu Ahad)" to be little (in reward) due to its few words. The Messenger of Allah (peace and blessings be upon him) said: "By Him in Whose Hand is my soul! Verily, this Surah '(Qul Huwa Allahu Ahad)' is equal to one third of the Qur'an."