What is the authenticity of the hadith about a Companion forgetting a surah and the Prophet, peace and blessings be upon him, informing him that it had been abrogated the previous night, and how can this be reconciled with Allah’s saying: "Indeed, it is We who sent down the Dhikr (the Qur’an) and indeed, We will be its Guardian"? And what is the extent of the authenticity of the statement attributed to Umar ibn al-Khattab, may Allah be pleased with him: "Let none of you say, 'I have taken the entire Qur'an,' for how would you know what the entire (Qur'an) is? Much of the Qur'an has gone"?

Al-Tabarani narrated a hadith about the Companions forgetting an entire surah that was abrogated in one night, and its authenticity has not been definitively confirmed or weakened. Ibn Taymiyyah also mentioned a similar report. Furthermore, Ibn Hibban and Al-Tabari narrated that Surat Al-Ahzab was equal in length to Surat Al-Baqarah, and that the verse of stoning was among its contents. As for what was attributed to Umar regarding the loss of much of the Quran, Abu Ubayd narrated it from Ibn Umar, and this hadith is interpreted as referring to abrogation (naskh). Abrogation does not contradict Allah's promise to preserve the Quran, because what is abrogated is not among what Allah has pledged to preserve. Allah abrogates some verses, as He says: "Whatever a verse We abrogate or cause to be forgotten, We bring forth [one] better than it or similar to it." This does not imply the loss of any part of the Quran.