Mishkat al-Masabih
The Excellent Qualities of the Qur'an — Hadith #2059
وَعَن ابْن عَبَّاس وَأنس بن مَالك رَضِيَ اللَّهُ عَنْهُمْ قَالَا: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: (إِذا زلزلت)
تعدل نصف الْقُرْآن (قل هُوَ الله أحد)
تعدل ثلث الْقُرْآن و (قل يَا أَيُّهَا الْكَافِرُونَ)
تَعْدِلُ رُبْعَ الْقُرْآنِ ". رَوَاهُ التِّرْمِذِيّ
Ibn ‘Abbās and Anas b. Mālik reported God’s messenger as saying that “When is shaken” (Qur’ān, 99) is equivalent to half the Qur’ān, “Say, He is God, One” (Qur’ān, 112) is equivalent to a third of the Qur’ān, and “Say, O infidels” (Qur’ān, 109) is equivalent to a quarter of the Qur’ān.
Tirmidhī transmitted it.