صحيح مسلم

It has been narrated on the authority of Abu Zubair who heard Jabir being questioned as to how many people were there on the Day of Hudaibiya. He replied: We were fourteen hundred. We swore fealty to him, and Umar was holding his hand while he was sitting under the tree (to administer the oath). The tree was a samura (a wild tree found in deserts). All of as took the oath of fealty at his hands except Jadd b. Qais al-Ansari who hid himself under the belly of his camel.