Sahih Muslim Book 10, Hadith Number 3890.

Jabir b. ‘Abdullah (Allah be pleased with them) reported: We were with Allah’s Messenger (may peace be upon him) in a journey and my camel meant for carrying water lagged behind. The rest of the hadith is the same and it is mentioned also: Allah’s Messenger (may peace be upon him) pricked it and then said to me: Ride in the name of Allah. He constantly made addition (in prayers for me) and went on saying. May Allah forgive you!