Sunan Abi Dawud 235

Abu Hurairah reported:The prayer (in congregation) began and people stood in their rows. The Messenger of Allah (May peace be upon him) came out (from his residence). When he stood at his proper place he recalled that he did not take a bath. He then said to the people: (Remain standing) at your places. Then he returned to his house and came out upon us after taking a bath while the drops of water were coming down from his head. We were standing in the rows (of prayer). This is the version of Ibn Harb. ‘Ayyash reported in his version: we kept on waiting for him while we were standing until he came upon us after he had taken a bath