From Sahih Bukhari (Hadith 2264):
Narrated Aisha:(the wife of the Prophet) Allah's Messenger (ﷺ) and Abu Bakr hired a man from the tribe of Bani-Ad-Dil as an expert guide who was a pagan (follower of the religion of the pagans of Quraish). The Prophet (ﷺ) and Abu Bakr gave him their two riding camels and took a promise from him to bring their riding camels in the morning of the third day to the Cave of Thaur
Reference: Bukhari 2264