الجامع المختصر لفضائل الآيات والسور
Virtues of the Qur'an's Chapters and Verses
It is equivalent to one-fourth of the Qur'ān
تَعْدِلُ رُبُعَ الْقُرْآنِ
Virtues of the Qur'an's Chapters and Verses 70
Ibn ʿAbbās reported that the Prophet ﷺ said:
“Qul huwa Allāhu aḥad (Sūrat al-Ikhlāṣ) is equivalent to one-third of the Qur'ān, and Qul yā ayyuhal kāfirūn (Sūrat al-Kāfirūn) is equivalent to one-fourth of the Qur'ān.” Reference: Al-Silsilah al-Ṣaḥīḥah 586.
قال رسول الله صلى الله عليه وسلم: (قل يا أيها الكافرون تعدل ربع القرآن).
Reference : Virtues of the Qur'an's Chapters and Verses 70