Sahih al-Bukhari, Book 65, Hadith 4840 (In-Book)

Narrated Jabir: We were one thousand and four hundred on the Day of Al-Hudaibiya.

حَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، حَدَّثَنَا سُفْيَانُ، عَنْ عَمْرٍو، عَنْ جَابِرٍ، قَالَ كُنَّا يَوْمَ الْحُدَيْبِيَةِ أَلْفًا وَأَرْبَعَمِائَةٍ‏.‏

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