While camped outside Mecca at Hudaybiyya, the Prophet Muhammad sends an emissary into the city. The Quraysh kill his camel, and he's barely allowed to leave.
The Prophet then tries to send Umar ibn Al-Khattab, but he refuses out of fear. Uthman, who had strong tribal ties with people in the city, is sent instead. However, he's prevented from leaving for three days, and Muslims fear the worst
Given the shakiness of the Muslims, the Prophet is inspired to renew their pledge to him in The Pledge of Ridhwan, and many verse of the Quran are revealed in praise of those who would stick with that pledge

Lecture notes available at http://www.why-quran.org/?p=612.

Subscribe at http://www.why-quran.org/subscribe to watch the lectures live and participate in the Q&A at the end of each class.

Video recording of this lecture + Q&A available on YouTube at https://www.youtube.com/watch?v=BaDUZ8PRumQ&list=PLpkB0iwLgfTat-Pgh4W3WFmupPamiC9UT.