Services to the Holy Qur'an
During the lifetime of the Holy Prophet (sa), six companions collated the entire Holy Quran into a single volume and Hazrat Sa‘d (ra) bin Ubadah was one of them.
*(Usdul Ghabah, Vol. 1, p. 503, Jariyah bin Majma’, Dar-ul-Kutub al-Ilmiyyah, Beirut, 2003) *
Hazrat Musleh Maud (ra), in regard to this, states that among the Ansar, the following names are of the well-known Huffaz [those who had committed the Holy Quran to memory]:
Ubadah bin Samit, Mu‘az, Mujamma bin Haritha, Fuzala bin Ubaid, Maslama bin Mukhallad, Abu Darda, Abu Zaid, Zaid bin Thabit, Ubayy bin Ka‘b, Sa‘d bin Ubadah and Umme Waraqah.
It is proven from historical sources that there were many companions (ra) who had memorised the Holy Quran.
(Dibacha Tafsir-ul-Quran, Anwarul Ulum, Vol. 20, p. 430)