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 1860 b
The above tradition has also been handed down through a different chain of transmitters.
وَحَدَّثَنَاهُ إِسْحَاقُ بْنُ إِبْرَاهِيمَ، حَدَّثَنَا حَمَّادُ بْنُ مَسْعَدَةَ، حَدَّثَنَا يَزِيدُ، عَنْ سَلَمَةَ، بِمِثْلِهِ .
Grade: Sahih