Sunan Ibn Majah, Book 33, Hadith 130 (In-Book) ⓘ
It was narrated that Abu Sa'eed bin Mu'alla said: "The Messenger of Allah said to me: 'Shall I not teach you the greatest Surah in the QUran before I leave the masjid?' Then the Propeht went to leave, so I reminded him, and he said: Al-hamdulillahi Rabbil-Alameen (All the praise is to Allah, the Lord of all that exists). It is the Seven Oft-Recited Verses, and it is the Grand Quran that has been given to me.'"
حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا غُنْدَرٌ، عَنْ شُعْبَةَ، عَنْ خُبَيْبِ بْنِ عَبْدِ الرَّحْمَنِ، عَنْ حَفْصِ بْنِ عَاصِمٍ، عَنْ أَبِي سَعِيدِ بْنِ الْمُعَلَّى، قَالَ قَالَ لِي رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ " أَلاَ أُعَلِّمُكَ أَعْظَمَ سُورَةٍ فِي الْقُرْآنِ قَبْلَ أَنْ أَخْرُجَ مِنَ الْمَسْجِدِ " . قَالَ فَذَهَبَ النَّبِيُّ ـ صلى الله عليه وسلم ـ لِيَخْرُجَ فَأَذْكَرْتُهُ فَقَالَ " { الْحَمْدُ لِلَّهِ رَبِّ الْعَالَمِينَ} وَهِيَ السَّبْعُ الْمَثَانِي وَالْقُرْآنُ الْعَظِيمُ الَّذِي أُوتِيتُهُ " .
also referenced under: Hadith 3785 (Reference) & Volume 5, Book 33, Hadith 3785 (DarusSalam)