Is it true that Uthman recited the entire Quran in one rak'ah? And who were the Companions who memorized the Quran? And does the Prophet's saying, "The most knowledgeable of people concerning lawful and unlawful matters is Mu'adh," or Ibn Mas'ud's saying, "The most knowledgeable of the Ummah concerning the Quran," mean that they were more knowledgeable than the Rightly Guided Caliphs?

It has been authentically reported that Uthman ibn Affan, may Allah be pleased with him, recited the entire Qur’an in one rak'ah. This has been narrated from him through numerous chains and has been authenticated by many scholars.

As for the number of Companions who memorized the Qur'an, there is no precise count of them. Some scholars have named a group of them, including: the Four Caliphs, Talhah, Sa'd, Ibn Mas'ud, Aishah, Hafsah, and Umm Salamah.

Regarding the one who recited the Qur'an best among the Ummah, Al-Tirmidhi narrated and Al-Albani authenticated from Anas ibn Malik that the Messenger of Allah, peace and blessings be upon him, said: "(The best reciter among them is) Ubayy ibn Ka'b." This does not mean that Ubayy was more knowledgeable than the Rightly Guided Caliphs. Rather, it means that he was the best reciter among the Companions at a specific time, or he became so after the era of the great and senior Companions had passed.