مُوَطَّأُ مَالِكٍ
Muwatta Malik 478
The Qur'an
وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ نَافِعٍ، عَنْ عَبْدِ اللَّهِ بْنِ عُمَرَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ إِنَّمَا مَثَلُ صَاحِبِ الْقُرْآنِ كَمَثَلِ صَاحِبِ الإِبِلِ الْمُعَقَّلَةِ إِنْ عَاهَدَ عَلَيْهَا أَمْسَكَهَا وَإِنْ أَطْلَقَهَا ذَهَبَتْ .
Yahya related to me from Malik from Nafi from Abdullah ibn Umar that the Messenger of Allah, (ﷺ), said, "A man who knows the Qur'an well is like a man who has a hobbled camel. If he takes care of it, he keeps it, and if he lets it go, it gets away."
Arabic/English book reference: Book 15, Hadith 6