While swearing fealty to the Prophet (ﷺ) we did not take the oath to death but that we would not run away (from the battlefield).
Sahih Muslim Book 33, Hadith 105
← Previous Hadith We were one thousand and four hundred on the Day of Hudaibiya. We swore fealty to hiin (the Holy Prophet) and 'Umar was holding the latter's hand (when he was sitting) under the tree (called) Samura (to administer the oath to the Companions). The narrator added: We took oath to the effect that we would not flee (from the battlefield if there was an encounter with the Meccans), but we did not take oath to fight to death.

Sahih Muslim Book 33, Hadith 104 Next Hadith → 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.

Sahih Muslim Book 33, Hadith 106