The Messenger of Allah ﷺ said, "Whoever recites "When the earth is shaken" [Zalzalah 99:1], it is counted for him as equal to half of the Quran. Whoever recites "Say, O disbelievers" [Kafirun 109:1], it is counted for him as equal to a quarter of the Quran. And whoever recites "Say, He is Allah, the One" [Ikhlas 112:1], it is counted for him as equal to a third of the Quran."
حدثنا محمد بن موسى الحرشي البصري حدثنا الحسن بن سلم بن صالح العجلي حدثنا ثابت البناني
قال رسول الله ﷺ من قرأ إذا زلزلت عدلت له بنصف القرآن ومن قرأ قل يا أيها الكافرون عدلت له بربع القرآن ومن قرأ قل هو الله أحد عدلت له بثلث القرآن
[Its isnad is daif]. Aqeeli also reported it in Al-Duafa 1/243 from the hadith of Muhammad bin Musa, with the same wording, and he said, "He is unknown in transmission and his hadith is not preserved," meaning Hasan bin Salm, who is unknown, as stated in Al-Taqrib as well. Tirmidhi's teacher in this chain is weak in reliability.There is also a report on this subject from Ibn Abbas [to come: 2894].