Was the verse, "Among the believers are men who have been true to their covenant with Allah," not compiled in the Mushaf of Abu Bakr Al-Siddiq, based on the narration of Zayd ibn Thabit, in which he mentions that he found it with Khuzaymah ibn Thabit Al-Ansari when the Mushaf was being copied during the era of Uthman?

Scholars, such as Ibn Kathir and Ibn Hajar, differed on the period in which the verse from Surah Al-Ahzab (from the believers are men who were true to what they covenanted with Allah) was lost: whether it was during the compilation of Abu Bakr or the compilation of Uthman.

Ibn Kathir favored that it was lost during the era of Abu Bakr, which is supported by the apparent meaning of Zayd ibn Thabit’s hadith, stating that he lost it when compiling the Quran during Abu Bakr's time, as he found it written with Khuzaymah Al-Ansari after searching for it throughout the Quran.

The meaning of "lost" here was not that it was unknown, but rather that it was not found in written form except with Khuzaymah, for Zayd remembered hearing it from the Prophet, peace and blessings be upon him.