´It was narrated that Abu Hurairah said that the Messenger of Allah(ﷺ) said:` "Qul Huwa Allahu ahad [Say: He is Allah, (the) One] is equivalent to one third of the Quran."
Related hadith on this topic
Explanation & Benefits
Maulana Ataullah Sajid
Benefits and Issues:
➊ The reward of Surah Al-Ikhlas is equal to one third of the Qur'an.
➋ The reason for its greatness is that it contains the exposition of Tawhid (the Oneness of Allah).
➌ Allah Ta'ala loves Tawhid and has extreme aversion to shirk (associating partners with Him).
Source: Commentary on Sunan Ibn Mājah by Mawlānā ‘Atā’ullāh Sājid, Page: 3787