Sahih Muslim Book - 33, Hadith - 4817

وَحَدَّثَنَا يَحْيَى بْنُ يَحْيَى أَخْبَرَنَا يَزِيدُ بْنُ زُرَيْعٍ عَنْ خَالِدٍ عَنِ الْحَكَمِ بْنِ عَبْدِ اللَّهِ بْنِ الأَعْرَجِ عَنْ مَعْقِلِ بْنِ يَسَارٍ قَالَ لَقَدْ رَأَيْتُنِى يَوْمَ الشَّجَرَةِ وَالنَّبِىُّ -صلى الله عليه وسلم- يُبَايِعُ النَّاسَ وَأَنَا رَافِعٌ غُصْنًا مِنْ أَغْصَانِهَا عَنْ رَأْسِهِ وَنَحْنُ أَرْبَعَ عَشْرَةَ مِائَةً قَالَ لَمْ نُبَايِعْهُ عَلَى الْمَوْتِ وَلَكِنْ بَايَعْنَاهُ عَلَى أَنْ لاَ نَفِرَّ.

It was narrated that Ma'qil bin Yasar said: "I remember the Day of the Tree, when the Prophet (s.a.w) received the people's oath of allegiance, and I was holding one of its branches away from his head, and we were fourteen hundred." He said: "We did not swear to fight to the death, but we swore not to flee."