Sahih al-Bukhari 2862

It is related that Jubayr ibn Hayya said, "'Umar sent people to the regions of the great countries to fight the idolaters. Al-Hurmuzan became Muslim and 'Umar said, 'I want to consult you about these lands.' He said, 'Yes, the example of them and the enemies of the Muslims who are in them is like a bird which has a head, two wings, and two legs. If one of its wings is broken, it gets up on its legs with one wing and the head. If the other wing is broken, it gets up on the two legs and the head. But if the head is broken, then the legs, wings and head are gone. The head is Chosroes, the wing is Caesar and the other wing is Faris. Therefore command the Muslims to make for Chosroes.'" Jubayr ibn Hayya said, "So 'Umar detailed us and put an-Nu'man ibn Muqarran in charge of us. When we reached enemy territory, the governor of Chosroes came out to us with forty thousand men. An interpreter stood up and said, 'Let a man among you speak to me.' Al-Mughira said, 'Ask whatever you like.' He said, 'Who are you?' He replied, 'We are people of the Arabs. We used to be in terrible hardship and severe affliction. We would suck hides and date-stones out of hunger and we wore camel hair and goat hair. We used to worship trees and stones. While we were like that, the Lord of the heavens and the Lord of the earths - may His mention be exalted and His immensity magnified! - sent us a Prophet from among ourselves whose father and mother we knew. Our Prophet, the Messenger of our Lord, may Allah bless him and grant him peace, has commanded us to fight you until you worship Allah alone or pay the jizya. Our Prophet, may Allah bless him and grant him peace, has informed us from the message of our Lord: whoever of us is killed will go to the Garden in bliss whose like he has never seen. Whoever of us remains will be your masters.' "An-Nu'man said [to al-Mughira when he objected to him delaying the battle), 'If Allah had made you be present at the like of it with the Prophet, may Allah bless him and grant him peace, he would not have made you regret waiting nor disgraced you. But I was present with the Messenger of Allah, may Allah bless him and grant him peace, in the fighting, and when he did not fight at the beginning of the day, he would wait until the winds blew and it was time for the prayer.' [meaning when the day was cooler]" [Faris was a region of Persia. An-Nu'man's comments are in answer to al-Mughira's objection to the decision to delay the attack.] II: When the ruler concludes a truce with the King of a country, does that hold for the rest of his people?