Sunan Ibn Majah 1236

Hamzah bin Mughirah bin Shu’bah narrated that his father said:“The Messenger of Allah (ﷺ) lagged behind (on a journey) and we reached the people when ‘Abdur Rahman bin ‘Awf had already led them in one Rak’ah of the prayer. When he realized that the Prophet (ﷺ) was there, he wanted to step back, but the Prophet (ﷺ) gestured to him that he should complete the prayer. He said: ‘You have done well, do the same in the future.’”