After the demise of the Holy Prophet (s.a.w.), as per his instructions, Hazrat Ali (a.s.) busied himself in collecting the Quran. From the third day itself[1] – i.e., Wednesday, he (a.s.) began this activity.
[1] As is mentioned in the narrations of Farikheen, the Holy Prophet (s.a.w) was buried on the night of Wednesday. Therefore there is not doubt that the work of collection of the Holy Quran began on Wednesday. This was when it began, but it is not clear how many days it took to complete this task. Then the narration of Furaate’ Kufi from Imam Mohammed Baqer (as), which has been recorded by Ibne’ Nadeem in his book Fehrist makes it clear that Ameerul Mo’meneen (as) took 3 days to compile the Quran. Please refer Tafseer’e Furaate’ Kufi, page 398/399; Behaarul Anwaar, volume 23 page 249; Al Fehrist, page 30. However in some traditions from Imam Mohammed Baqer (as), which he narrates from his forefathers (as), that after the seventh day of the martyrdom of the Holy Prophet (saw), Hazrat Ali (as) delivered a sermon - Khubae’ Wasilah. In some copies it is nine days, this sermon was delivered after Hazrat Ali (as) completed the compilation of the Quran. Al Kaafi, volume 8 page 17; At Tawheed, page 73; Amali Sudooq, page 320; Amali Shaykh Tusi, volume 1 page 263; Behaarul Anwaar, volume 4 page 122 and volume 77 page 382.