Al-Muddaththir 74:3

As narrated from Jabir ibn Abdullah in Bukhari and Muslim, the Prophet described the period when revelation had paused (fatrat al-wahy): "As I was walking, I heard a voice from the sky. I raised my eyes, and there was the angel who had come to me at Hira, sitting on a throne between heaven and earth. I was seized with fear, returned home and said: 'Wrap me up, wrap me up.'" Thereupon the verses were revealed: "O you wrapped in your cloak! Arise and warn, and magnify your Lord." From then on, revelation continued without interruption.

Buhârî 4922; Müslim 161

Surah al-Muddaththir is Meccan and among the earliest revelations; according to the report from Jabir ibn Abdullah in Bukhari, its opening verses came down after the pause (fatra) that followed the first revelation. With the command 'Arise and warn' it inaugurated the mission of open proclamation. The later verses of the surah are reported to have been revealed concerning al-Walid ibn al-Mughira, a Meccan notable who called the Quran 'sorcery handed down'.

Buhârî rivayeti (Câbir hadisi); Vâhidî, Esbâbü'n-Nüzûl