(18) باب الْغَسْلِ بَعْدَ الْحَرْبِ وَالْغُبَارِ
Narrated `Aisha:
When Allah's Messenger (ﷺ) returned on the day (of the battle) of Al-Khandaq (i.e. Trench), he put down his arms and took a bath. Then Gabriel whose head was covered with dust, came to him saying, "You have put down your arms! By Allah, I have not put down my arms yet." Allah's Messenger (ﷺ) said, "Where (to go now)?" Gabriel said, "This way," pointing towards the tribe of Bani Quraiza. So Allah's Messenger (ﷺ) went out towards them .
Reference: Sahih al-Bukhari 2813
In-book reference: Book 56, Hadith 29
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 4, Book 52, Hadith 68