Narrated Anas bin Malik:
that the Messenger of Allah (ﷺ) said: "Whoever recites Idha Zulzilat, it equals half of the Qur'an for him. Whoever recites: Qul Ya Ayyuhal-Kafirun it equals a fourth of the Qur'an for him. And whoever recites: Qul Huwa Allahu Ahad it equals a third of the Qur'an for him." (FR)
English reference (FR): Vol. 5, Book 42, Hadith 2893 (FR)
Arabic reference (FR): Book 45, Hadith 3138 (FR)