Will the Qur'an be a proof against someone who memorized parts of it and reviewed them for a long time but suffers from frequent forgetfulness, or will it be a proof for him on the Day of Resurrection? And what should he do to overcome this problem?

Being occupied with the Qur'an and memorizing it is among the best deeds, and a Muslim is rewarded for their effort to memorize it, even with forgetfulness and difficulty in completing it, due to the saying of the Prophet, peace and blessings be upon him: "The one who is proficient in the Qur'an will be with the noble and righteous scribes (angels), and the one who recites the Qur'an and stutters over it, finding it difficult, will have two rewards." The meaning of "stutters" is hesitates in his recitation due to weak memorization, so he has the reward for recitation and the reward for the difficulty. This does not mean that his reward is greater than that of the one proficient in the Qur'an; rather, the proficient one is better and has a greater reward. The Qur'an is an argument for the Muslim if he acts upon it, and an argument against him if he turns away from it, due to the saying of the Prophet, peace and blessings be upon him: "And the Qur'an is either a proof for you or against you."