(23) باب اسْتِذْكَارِ الْقُرْآنِ وَتَعَاهُدِهِ
Narrated Ibn `Umar:
Allah's Messenger (ﷺ) said, "The example of the person who knows the Qur'an by heart is like the owner of tied camels. If he keeps them tied, he will control them, but if he releases them, they will run away."
Reference: Sahih al-Bukhari 5031
In-book reference: Book 66, Hadith 53
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 6, Book 61, Hadith 549