It is narrated from Hazrat Anas bin Malik (may Allah be pleased with him) that once the Prophet (peace and blessings be upon him) saw a man who was walking while driving a camel and was unable to walk further. The Prophet (peace and blessings be upon him) told him to ride it. He said, "This is a sacrificial animal." The Prophet (peace and blessings be upon him) said to him, "Ride it, even if it is for sacrifice."
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 12040