Sunan an Nasai
1095
Sahih+2

It was narrated that Abu Sa'eed Al-Khudri said:"My two eyes saw the traces of water and mud on the forehead and nose of the Messenger of Allah (ﷺ), from his praying Qiyam on the night of the twenty-first

SahihAbu Ghuddah
SahihAl-Albani