Imām Muḥammad ibn ʿAlī al-Shawkānī [d. 1250 AH] related from Imām Muḥammad ibn Aḥmad al-Qurṭubī [d. 671 AH] who said:

It is necessary [for the one who memorises the Qurʾān] to learn the rulings contained therein, as this will facilitate him becoming acquainted with Allāh’s intent and what He has made obligatory on him. Thus, he is able to derive benefit from what he reads and act upon what he recites.

How detestful is it that a person carries the Qurʾān [through memorisation], reciting its laws and rulings without having to consult it, but remains completely oblivious to the meaning of what he relates.

How can he hope to enact what he does not understand? How distasteful is it for him to then have to ask concerning the jurisprudence of what he himself has just recited due to his own ignorance? There is no closer parable for such a person than a donkey who carries volumes [of books]. It is also appropriate for him to be able to distinguish the chapters that are Makkī [revealed before the hijrah] and Madanī [revealed after it] so that he is able to differentiate between that which Allāh addressed the believers with in the beginning of Islām, and what He called them towards at the conclusion [of the message]. [He can then also be aware of] what was made obligatory when Islām started, and the legislations which were added later. As the Madanī chapters contain that which abrogates the Makkī chapters in the majority of the Qurʾān.

Source: Fatḥ al-Qadīr 1: 13-14
Translated by: Riyāḍ al-Kanadī