Riyad as-Salihin, 1010

Abu Sa'id Al-Khudri (May Allah be pleased with him) reported about Surat Al-Ikhlas (Chapter 112):

The Messenger of Allah (ﷺ) said, "By Him in Whose Hand my soul is, it is equivalent to one-third of the Qur'an." According to another version, he (ﷺ) said to his Companions, "Is anyone of you incapable of reciting one-third of the Qur'an in one night?" They considered it burdensome and said: "O Messenger of Allah, which of us can afford to do that?" He (ﷺ) said, "Surat Al-Ikhlas [Say: He is Allah (the) One] is equivalent to one-third of the Qur'an." [Al- Bukhari].

وعن أبي سعيد الخدري رضي الله عنه أن رسول الله صلى الله عليه وسلم قال في‏:‏‏{‏ قل هو الله أحد‏}‏‏:‏‏"‏ والذي نفسي بيده، إنها لتعدل ثلث القرآن‏"‏‏.‏ وفي رواية‏:‏ أن رسول الله صلى الله عليه وسلم قال لأصحابه‏:‏‏"‏ أيعجز أحدكم أن يقرأ بثلث القرآن في ليلة‏"‏ فشق ذلك عليهم، وقالوا‏:‏ أينا يطيق ذلك يارسول الله‏:‏ فقال ‏:‏‏"‏ ‏{‏قل هو الله أحد‏}‏ ثلث القرآن‏.‏‏"‏‏.‏ ‏(‏‏(‏ رواه البخاري‏)‏‏)‏‏.‏

References1 variant

In-Book Reference: Book 8, Hadith 20

Sharh · explanationclick to expand

Guidance from the Hadiths: 1) Surat al-Ikhlās is called as such because Allah Almighty devoted it to Himself, not mentioning in it but His names and attributes (the Arabic term Ikhlās means sincerity and devotion). It comprises the oneness of Allah Almighty. 2) Tawhid (belief in the oneness of Allah) covers one third of the Qur’an, whose sciences revolve around three branches: Tawhid, rulings, and recompense. Hence, Surat al-Ikhlās is a third of the Qur’an, because it contains pure Tawhid. 3) In declaring Surat al-Ikhlās a third of the Qur’an, the Hadith refers to the reward and it does not mean that this Surah is sufficient in place of the other meanings in the Qur’an.

Related hadiths3