Sunan an Nasai
1555
Sahih+2

It was narrated from Abu Bakrah that:The Prophet (ﷺ) offered the fear prayer with those who were behind him, praying two rak'ahs (with them) and two rak'ahs with those who came after them, so the Prophet (ﷺ) prayed four rak'ahs and the others each prayed two rak'ahs

SahihAbu Ghuddah
SahihAl-Albani