Abdullah bin Masud reported,

We were with the Messenger of Allah ﷺ, and he arranged one row behind him and another row facing the enemy. They were all engaged in the prayer.He said the takbir, and they all said the takbir together. He then prayed one rakah with the row directly behind him, while the other row remained facing the enemy.Then those who had prayed moved away, and the other group came forward, and he prayed one rakah with them.Then those with whom he had prayed the second rakah stood up and completed their remaining rakah in their place. After that, they moved to take the position of the other group, and the other group came forward and completed their remaining rakah.

حدثنا عبد الرزاق حدثنا سفيان عن خصيف عن أبي عبيدة

عن عبد الله قال

كنا مع رسول الله ﷺ فصف صفا خلفه وصف موازي العدو قال وهم في صلاة كلهم قال وكبر وكبروا جميعا فصلى بالصف الذي يليه ركعة وصف موازي العدو قال ثم ذهب هؤلاء وجاء هؤلاء فصلى بهم ركعة ثم قام هؤلاء الذين صلى بهم الركعة الثانية فقضوا مكانهم ثم ذهب هؤلاء إلى مصاف هؤلاء وجاء أولئك فقضوا ركعة