Is it permissible to memorize the Quran while walking?

There is nothing to prevent memorizing and reciting the Qur’an in this manner, based on the Almighty’s saying: "Those who remember Allah while standing or sitting or [lying] on their sides." It is preferable to recite the Qur’an in the most complete state by sitting facing the Qibla, as An-Nawawi mentioned in Al-Majmoo'.