Sahih al-Bukhari 5036
Sahih al-Bukhari · Book 66: Virtues of the Qur'an · Teaching the Qur'an to the children
Narrated Sa`id bin Jubair:
حَدَّثَنَا يَعْقُوبُ بْنُ إِبْرَاهِيمَ ، حَدَّثَنَا هُشَيْمٌ ، أَخْبَرَنَا أَبُو بِشْرٍ ، عَنْ سَعِيدِ بْنِ جُبَيْرٍ ، عَنِ ابْنِ عَبَّاسٍ ـ رضى الله عنهما ـ جَمَعْتُ الْمُحْكَمَ فِي عَهْدِ رَسُولِ اللَّهِ صلى الله عليه وسلم فَقُلْتُ لَهُ وَمَا الْمُحْكَمُ قَالَ الْمُفَصَّلُ.
Ibn `Abbas said, "I have learnt all the Muhkam Suras during the life time of Allah's Messenger (ﷺ)." I said to him, 'What is meant by the Muhkam?" He replied, "The Mufassal."