Sahih Muslim
Sahih Muslim 1856 e
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
Arabic hadith text
حَدَّثَنَا سَعِيدُ بْنُ عَمْرٍو الأَشْعَثِيُّ، وَسُوَيْدُ بْنُ سَعِيدٍ، وَإِسْحَاقُ بْنُ إِبْرَاهِيمَ، وَأَحْمَدُ، بْنُ عَبْدَةَ - وَاللَّفْظُ لِسَعِيدٍ قَالَ سَعِيدٌ وَإِسْحَاقُ أَخْبَرَنَا وَقَالَ الآخَرَانِ، حَدَّثَنَا سُفْيَانُ، عَنْ عَمْرٍو، عَنْ جَابِرٍ، قَالَ كُنَّا يَوْمَ الْحُدَيْبِيَةِ أَلْفًا وَأَرْبَعَمِائَةٍ فَقَالَ لَنَا النَّبِيُّ صلى الله عليه وسلم "أَنْتُمُ الْيَوْمَ خَيْرُ أَهْلِ الأَرْضِ " . وَقَالَ جَابِرٌ لَوْ كُنْتُ أُبْصِرُ لأَرَيْتُكُمْ مَوْضِعَ الشَّجَرَةِ
Translation
It has been narrated (through a different chain of transmitters) on the authority of Jabir who said
We were one thousand and four hundred on the Day of Hudaibiya when the Prophet (ﷺ) said to us: Today you are the best people on the earth. And Jabir said: If I had the eyesight, I could show you the place of the tree.