Sahih Muslim
The Book on Government (Kitab Al-Imara)
Book Number: 020 / Hadith Number: 4590
It has been narrated on the authority of Yazid b. Abu Ubaid (the freed slave of Salama b. al-Akwa') who said: 1 asked Salama as to what effect he had sworn fealty to the Messenger of Allah (may peace be upon him) on the Day of Hudaibiya. He said: To the effect that we will die fighting.