Sahih al-Bukhari 3159, 3160

Al-Fadl ibn Yaʿqub narrated to us: ʿAbd Allah ibn Jaʿfar al-Raqqi narrated to us: al-Muʿtamir ibn Sulayman narrated to us: Saʿid ibn ʿUbayd Allah al-Thaqafi narrated to us: Bakr ibn ʿAbd Allah al-Muzani and Ziyad ibn Jubayr narrated to us, from Jubayr ibn Hayya, who said: ʿUmar sent people from the various regions to fight the polytheists. Al-Hurmuzan embraced Islam, and ʿUmar said, ‘I want to consult you about these campaigns of mine.’ He said, ‘Yes. The example of these campaigns and the people in them who are enemies of the Muslims is that of a bird with a head, two wings, and two legs. If one wing is broken, the two legs, the other wing, and the head can still support it. If the other wing is broken, the two legs and the head can still support it. But if its head is crushed, the two legs, the two wings, and the head are all lost. The head is Khosrau; one wing is Caesar; and the other wing is Persia. So order the Muslims to march against Khosrau.’ Bakr and Ziyad both related from Jubayr ibn Hayya, who said: ʿUmar then called us to the campaign and appointed al-Nuʿman ibn Muqarrin over us. When we were in enemy territory, Khosrau’s governor came out against us with forty thousand men. An interpreter stood up and said, ‘Let one of you speak to me.’ Al-Mughira said, ‘Ask whatever you wish.’ He asked, ‘Who are you?’ He replied, ‘We are Arabs. We lived in great hardship and distress: from hunger we sucked leather and date stones; we wore wool and hair; and we worshipped trees and stones. While we were in that state, the Lord of the heavens and the earth—exalted is His mention and magnificent is His majesty—sent to us a Prophet from among ourselves, whose father and mother we know. Our Prophet, the Messenger of our Lord (ﷺ), commanded us to fight you until you worship Allah alone or pay the jizya. Our Prophet (ﷺ) informed us of our Lord’s message: whoever among us is killed will enter Paradise, in a bliss the like of which he has never seen; and whoever remains alive will become master over your persons.’ Al-Nuʿman said, ‘Perhaps Allah will let you witness something like this alongside the Prophet (ﷺ), and you would neither regret it nor be disgraced. But I witnessed battles with the Messenger of Allah (ﷺ): when he did not fight at the beginning of the day, he would wait until the winds began to blow and the prayer times arrived.’