When the Prophet (ﷺ) put his feet in the stirrup and the she-camel got up carrying him he would start reciting Talbiya at the mosque of Dhul-Hulaifa.
Sahih al-Bukhari Book 56, Hadith 81
← Previous Hadith Somebody asked Al-Bar-a bin `Azib, "Did you flee deserting Allah's Messenger (ﷺ) during the battle of Hunain?" Al-Bara replied, "But Allah's Messenger (ﷺ) did not flee. The people of the Tribe of Hawazin were good archers. When we met them, we attacked them, and they fled. When the Muslims started collecting the war booty, the pagans faced us with arrows, but Allah's Messenger (ﷺ) did not flee. No doubt, I saw him on his white mule and Abu Sufyan was holding its reins and the Prophet (ﷺ) was saying, 'I am the Prophet (ﷺ) in truth: I am the son of `Abdul Muttalib.' "

Sahih al-Bukhari Book 56, Hadith 80 Next Hadith → The Prophet (ﷺ) met them (i.e. the people) while he was riding an unsaddled horse with his sword slung over his shoulder.

Sahih al-Bukhari Book 56, Hadith 82