What are the hadiths that the Messenger of Allah, may Allah bless him and grant him peace, asked to be memorized?

The Sunnah is a primary source of legislation, and the Qur'an commands us to accept everything that the Messenger of Allah, peace and blessings be upon him, brought. Therefore, memorizing the Sunnah is recommended. The importance of memorization lies in the content of the text. It is preferable to memorize the hadiths related to rulings (obligations and prohibitions) first, then the sunan (recommended and disliked acts).

Beneficial books for a beginner in hadiths of rulings include: "'Umdat al-Ahkam" and "Bulugh al-Maram." For etiquette and morals: "Al-Adab al-Mufrad" and "Riyadh al-Salihin." It is also recommended to memorize "Al-Arba'in al-Nawawiyyah" and its continuation by Ibn Rajab.

It is desirable to memorize the exact wording of the hadiths, but if difficult, understanding their meanings suffices, except for hadiths of supplications and remembrances, whose exact wording must be memorized precisely because they are tawqifiyyah (divinely ordained and unalterable). Among the useful books on remembrances is "Kitab al-Adhkar" by Imam al-Nawawi.