Sunan Abi Dawud Book 2, Hadith 155
when the Iqamah was pronounced and the Messenger of Allah (ﷺ) saw that they (the people) were small in number, he would sit down, nd would not pray; but when he saw them (the people) large in number, he would pray.
the Iqamah was pronounced (for the night prayer) and the Messenger of Allah (ﷺ) remained engaged in talking (to a person) in the corner of the mosque. He did not begin prayer until the people slept.
This tradition has been transmitted through a different chain of narrators in a similar way by ‘Ali b. Abi Talib.