What is the ruling on one who vows to dedicate two specific days to reading the Qur'an, while believing that dedicating a specific day to reading the Qur'an is an innovation (bid'ah)?

Reciting the Quran is always commendable. If a Muslim vows to recite the Quran on only two days of the week with the intention of not reciting it on other days, this is disliked for him, as it is a vow to abandon something recommended. It is preferable for him to offer an expiation for an oath (kaffarat yameen) so that he can recite the Quran at all times.

However, if he vows to recite on two days without the intention of refraining from reciting on other days, he must fulfill his vow, as it is a vow of obedience. This is not considered a forbidden restriction, bearing in mind that vowing is originally disliked.

If the vow leads to forgetting the Quran, the one who made the vow must break it, offer an expiation for an oath, and return to reciting the Quran regularly. This is because forgetting the Quran due to negligence is a sin, and some scholars have considered it among the major sins. There are reports indicating the severity of the sin of forgetting the Quran after memorizing it. Ibn Taymiyyah said: "Indeed, forgetting the Quran is among the sins," and Abu Al-Aliyah said: "We used to consider it one of the greatest sins for a man to learn the Quran and then neglect it until he forgets it."