Sunan Ibn Majah, Chapter: The Chapters of Establishing the Prayer and the Sunnah Regarding Them

"I went out on a rainy night (for congregational prayer), and when I came back I asked for the door to be opened. My father said: 'Who is this?' I said: 'Abu Malih.' He said: 'We were with the Messenger of Allah (saw) at Hudaybiyah and it rained a little, such that the soles of our sandals did not get wet. The announcer of the Messenger of Allah (saw) called out: 'Perform your prayer at your camps.'" (Sahih)