The ruling on one who memorized the Qur'an and then forgot it

Question:
May Allah reward you. The questioner, M.R. from al-Ta'if, asks: Is there a sin on the one who memorized something from the Noble Qur'an, or memorized the entire Qur'an, and then forgot it, and was unable to review it for any reason, such as illness, or being occupied with a permissible matter, or otherwise?

Answer:
He owes no sin, but he has lost a great blessing. So the Muslim whom Allah has blessed with the memorization of the Qur'an should give thanks for this blessing and should maintain the Qur'an by increasing its recitation and review, for the Prophet (peace and blessings be upon him) informed us that this Qur'an is more likely to slip away from its holder than camels from their pens, or more likely to escape from their pens. It is obligatory for the one whom Allah has blessed with the memorization of the Qur'an, or part of it, to preserve this blessing, and to review his memorization and repeat it. This is not difficult for him. A person who memorizes the Qur'an can recite the Qur'an and review it while walking, while riding, while on his bed, and while at work. This is not something that is difficult. Allah the Exalted said: ? And forgetting only occurs from prolonged heedlessness regarding its recitation, prolonged heedlessness and being occupied away from it, and this is not befitting for the Muslim. Yes.