Jabir reported that the people grew thirsty on the day of Hudaybiyyah, while the Messenger of Allah ﷺ had a small water vessel in front of him from which he performed ablution. The people then came toward him.The Messenger of Allah ﷺ asked, "What is the matter with you?"They replied, "Messenger of Allah, we have no water to perform ablution with, nor any to drink, except what is in your vessel."The Prophet ﷺ then placed his hand in the vessel, and water began to gush forth from between his fingers like springs. So we drank and performed ablution.I asked Jabir, "How many were you that day?"He replied, "Even if we had been a hundred thousand, it would have sufficed us. We were fifteen hundred."
عطش الناس يوم الحديبية ورسول الله ﷺ بين يديه ركوة، فتوضأ منها، ثم أقبل الناس نحوه فقال رسول الله ﷺ: ما لكم؟ قالوا: يا رسول الله ليس عندنا ماء نتوضأ به، ولا تشرب إلا ما في ركوتك. قال: فوضع النبي ﷺ يده في الركوة، فجعل الماء يفور من بين أصابعه كأمثال العيون، قال: فشربنا وتوضأنا فقلت لجابر: كم كنتم يومئذ؟ قال: لو كنا مائة ألف لكفانا، كنا خمس عشرة مائة.
Bukhari narrated it in the Book of Military Expeditions (4152), and Muslim in the Book of Leadership (73:1856), both through the route of Husayn (that is, Ibn Abdul-Rahman), from Salim bin Abu Jaad, from Jabir, who related it as mentioned.His statement, "We were fifteen hundred," and in the narration of Amr bin Dinar from Jabir it comes as, "We were fourteen hundred." These can be reconciled by saying that they numbered more than fourteen hundred. Whoever said fifteen hundred rounded the fraction up, and whoever said fourteen hundred dropped it.As for the statement of Abdullah bin Abu Awfa, "Thirteen hundred," it can be understood as reflecting what he himself observed, while others observed the additional number. Or it may be that the number he mentioned refers to those present at the very start of setting out from Madinah, with the additional ones catching up with them afterward. Or the number he mentioned refers to the count of fighters, while the additional number consisted of followers such as servants, women, and children who had not yet reached puberty.