Jami' at-Tirmidhi 2884

حَدَّثَنَا مُحَمَّدُ بْنُ إِسْمَاعِيلَ، قَالَ حَدَّثَنَا الْحُمَيْدِيُّ، قَالَ حَدَّثَنَا سُفْيَانُ بْنُ عُيَيْنَةَ، فِي تَفْسِيرِ حَدِيثِ عَبْدِ اللَّهِ بْنِ مَسْعُودٍ قَالَ مَا خَلَقَ اللَّهُ مِنْ سَمَاءٍ وَلاَ أَرْضٍ أَعْظَمَ مِنْ آيَةِ الْكُرْسِيِّ ‏.‏ قَالَ سُفْيَانُ لأَنَّ آيَةَ الْكُرْسِيِّ هُوَ كَلاَمُ اللَّهِ وَكَلاَمُ اللَّهِ أَعْظَمُ مِنْ خَلْقِ اللَّهِ مِنَ السَّمَاءِ وَالأَرْضِ ‏.‏

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

Reference

Jami' at-Tirmidhi 2884

In-book

Book 45, Hadith 10