The Messenger of Allah ﷺ said, "Say, He is Allah, the One, equals a third of the Quran."
حدثنا أبو بكر حدثنا خالد بن مخلد حدثنا سليمان بن بلال حدثني سهيل عن أبيه
قال رسول الله ﷺ قل هو الله أحد تعدل ثلث القرآن
[Its isnad is sahih] Reference: Tirmidhi related it in "Virtues of the Quran," the chapter on what has been said about Surah Ikhlas and Surah Izaa Zulzilat, 2:899, from the hadith of Khalid bin Mukhlad through this same chain, and he said, hasan sahih.