Hadith 1002
Abu Musa Al-Ash'ari (May Allah be pleased with him) reported:
عن أبي موسى رضي الله عنه عن النبي صلى الله عليه وسلم قال "تعاهدوا هذا القرآن فوالذي نفس محمد بيده لهو أشد تفلتًا من الإبل في عقلها" . ((متفق عله)).
The Prophet (ﷺ) said, "Read the Qur'an regularly. By the One in Whose Hand Muhammad's soul is, it escapes from memory faster than a camel does from its tying ropes." [Al-Bukhari and Muslim].
In plain words
Revisit the Qur'an steadily, because what you have memorised slips from the mind quickly, faster than a camel breaks loose and runs off if you leave it alone.
Reference : Riyad as-Salihin 1002 In-book reference : Book 8, Hadith 12