Abdullah bin Abbas reported,

The Messenger of Allah ﷺ stood up to pray and the people stood with him. He said the takbir and they said it as well. Then he bowed, and a group of them bowed with him. Then he prostrated and they prostrated with him.When he rose for the second rakah, those who had prostrated with him stepped back to stand guard over their brothers, while the other group came forward and bowed and prostrated with the Prophet ﷺ. All the people were engaged in the prayer and saying the takbir, but they were guarding one another.

Nasai 1535

Sahih

أخبرني عمرو بن عثمان بن سعيد بن كثير عن محمد عن الزبيدي عن الزهري عن عبيد الله بن عبد الله بن عتبة أن

عبد الله بن عباس قال

قام رسول الله ﷺ وقام الناس معه فكبر وكبروا ثم ركع وركع أناس منهم ثم سجد وسجدوا ثم قام إلى الركعة الثانية فتأخر الذين سجدوا معه وحرسوا إخوانهم وأتت الطائفة الأخرى فركعوا مع النبي ﷺ وسجدوا والناس كلهم في صلاة يكبرون ولكن يحرس بعضهم بعضا

النسائي 1535صحيح
Contents
Reference
Commentary
Ayat
Collection
Sunan Nasai Sughra
Book
Prayer of fear
Chapter
Prayer of fear
Numbering
Darussalam 1535
Nasai 1535