Once the Prophet (ﷺ) fell ill and did not offer the night prayer (Tahajjud prayer) for a night or two. A woman (the wife of Abu Lahab) came to him and said, "O Muhammad ! I do not see but that your Satan has left you." Then Allah revealed (Surat-Ad-Duha): 'By the fore-noon, and by the night when it darkens (or is still); Your Lord has not forsaken you, nor hated you.' (93)
Sahih al-Bukhari Book 66, Hadith 5
← Previous Hadith Allah sent down His Divine Inspiration to His Apostle continuously and abundantly during the period preceding his death till He took him unto Him. That was the period of the greatest part of revelation; and Allah's Messenger (ﷺ) died after that.

Sahih al-Bukhari Book 66, Hadith 4 Next Hadith → (The Caliph `Uthman ordered Zaid bin Thabit, Sa`id bin Al-As, `Abdullah bin Az-Zubair and `Abdur- Rahman bin Al-Harith bin Hisham to write the Qur'an in the form of a book (Mushafs) and said to them. "In case you disagree with Zaid bin Thabit (Al-Ansari) regarding any dialectic Arabic utterance of the Qur'an, then write it in the dialect of Quraish, for the Qur'an was revealed in this dialect." So they did it.

Sahih al-Bukhari Book 66, Hadith 6