Compilation of the Quran in the Era of Abu Bakr

إِنَّا نَحۡنُ نَزَّلۡنَا ٱلذِّكۡرَ وَإِنَّا لَهُۥ لَحَٰفِظُونَ

Direct Cause:
After the Battle of Yamama (12 AH), seventy Quran memorizers were martyred. Umar ibn al-Khattab feared that portions of the Quran might be lost, and urged Abu Bakr to compile it.

Methodology:

Nothing was recorded unless two reliable witnesses attested it was written in the Prophet's presence.
Zaid ibn Thabit, the scribe of revelation, was entrusted with the compilation.
Verses were ordered within each surah — but surahs were not yet arranged in a fixed order.

Result: The compiled sheets were kept with Abu Bakr, then passed to Umar, then to Hafsa.

Question: Who suggested compiling the Quran to Abu Bakr and why?

Answer: Umar ibn al-Khattab — after seventy Quran reciters were martyred at the Battle of Yamama.