Ma'mar bin Rashid معمر بن راشد · The Book of the Fear Prayer

The Messenger of Allah (ﷺ) prayed at Dhi Qarad and the people formed two rows behind him, one row behind him and one row facing the enemy. He led those who were behind him in praying one rak'ah, then they went and took the place of the others, and the others came and he led them in praying one rak'ah, and they did not make it up.