(18) باب اسْتِحْبَابِ مُبَايَعَةِ الإِمَامِ الْجَيْشَ عِنْدَ إِرَادَةِ الْقِتَالِ وَبَيَانِ بَيْعَةِ الرِّضْوَانِ تَحْتَ الشَّجَرَةِ
This hadith has been narrated on the authority of Yunus with the same chain of transmitters.
Reference: Sahih Muslim 1858 b
In-book reference: Book 33, Hadith 115
USC-MSA web (English) reference(deprecated numbering scheme): Book 20, Hadith 4587