حَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، حَدَّثَنَا لَيْثُ بْنُ سَعْدٍ، ح وَحَدَّثَنَا مُحَمَّدُ بْنُ رُمْحٍ، أَخْبَرَنَا اللَّيْثُ، عَنْ أَبِي الزُّبَيْرِ، عَنْ جَابِرٍ، قَالَ كُنَّا يَوْمَ الْحُدَيْبِيَةِ أَلْفًا وَأَرْبَعَمِائَةٍ فَبَايَعْنَاهُ وَعُمَرُ آخِذٌ بِيَدِهِ تَحْتَ الشَّجَرَةِ وَهِيَ سَمُرَةٌ ‏.‏ وَقَالَ بَايَعْنَاهُ عَلَى أَلاَ نَفِرَّ ‏.‏ وَلَمْ نُبَايِعْهُ عَلَى الْمَوْتِ.
Translation
It has been narrated on the authority of Salim b. Abu al-Ja'd who said

I asked Jabir b. 'Abdullah about the number of the Companions (of the Prophet who took the oath of fealty under) the tree. He said: If we were a hundred thousand, it (i. e. the water in the well at Hudaibiya) would have sufficed us, but actually we were one thousand and five hundred.