Sahih Bukhari Volume 003, Book 036, Hadith Number 464.
Narated By 'Aisha : The Prophet and Abu Bakr employed a (pagan) man from the tribe of Bani Ad-Dail and the tribe of Bani 'Abu bin 'Adi as a guide. He was an expert guide and he broke the oath contract which he had to abide by with the tribe of Al-'Asi bin Wail and he was on the religion of Quraish pagans. The Prophet and Abu Bakr had confidence in him and gave him their riding camels and told him to bring them to the Cave of Thaur after three days. So, he brought them their two riding camels after three days and both of them (The Prophet and Abu Bakr) set out accompanied by 'Amir bin Fuhaira and the Dili guide who guided them below Mecca along the road leading to the sea-shore.