Sahih Muslim Book 7, Hadith Number 3049.
Chapter : It is permissible to ride the sacrificial animal (camel) for one who is in need of it.
Anas reported that Allah’s Messenger (may peace be upon him) happened to pass by a person who was driving a sacrificial camel, whereupon he (the Holy Prophet) said: Ride on It. He said: It is a sacrificial camel. Thereupon he (the Holy Prophet) said twice or thrice: Ride on it.