Narrated Abu Hurairah:
that the Messenger of Allah (ﷺ) said: "Qul Huwa Allahu Ahad is equal to a third of the Qur'an." (IT)
English reference (IT): Vol. 5, Book 42, Hadith 2899 (IT)
Arabic reference (IT): Book 45, Hadith 3145 (IT)