Sahih
Muslim
صحيح مسلم
33
The Book on Government
كتاب الإمارة
Chapter 18: It is recommended for the army to swear allegiance to the ruler when intending to fight, and an account of Bay'at Ar-Ridwan beneath the tree
باب اسْتِحْبَابِ مُبَايَعَةِ الإِمَامِ الْجَيْشَ عِنْدَ إِرَادَةِ الْقِتَالِ وَبَيَانِ بَيْعَةِ الرِّضْوَانِ تَحْتَ الشَّجَرَةِ
Sahih Muslim 1858 b
This hadith has been narrated on the authority of Yunus with the same chain of transmitters.
وَحَدَّثَنَاهُ يَحْيَى بْنُ يَحْيَى، أَخْبَرَنَا خَالِدُ بْنُ عَبْدِ اللَّهِ، عَنْ يُونُسَ، بِهَذَا الإِسْنَادِ.
Grade: Sahih