Narrated 'Abdullah bin Mas'ud:
"Allah has not created in the heavens nor in the earth what is more magnificent than Ayat Al-Kursi." Sufyan said: "Because Ayat Al-Kursi is the Speech of Allah, and Allah's Speech is greater than Allah's creation of the heavens and the earth."
English reference: Vol. 5, Book 42, Hadith 2884
Arabic reference: Book 45, Hadith 3122