*Hadith: 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

Bismilahirrahmanirrahim 

✦ Narrated Abdullah Radi Allahu anhu The Prophet (ﷺ) said, "It is a bad thing that some of you say, 'I have forgotten such-and-such verse of the Qur'an,' for indeed, he has been caused (by Allah) to forget it. So you must keep on reciting the Qur'an because it escapes from the hearts of men faster than camel do."

Sahih Bukhari,Book 61, 550

✦ Narrated Ibn Umar radi allahu anhu 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."

Sahih Bukhari, Book 61, 549