Maliks Muwatta Book 15, Hadith Number 6.

Section : About the Qur’an.

Yahya related to me from Malik from Nafi from Abdullah ibn Umar that the Messenger of Allah, may Allah bless him and grant him peace, 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.”