Musnad Ahmad 32:671

Husayn narrated to us, Khalaf ibn Khalifah narrated to us, from Hafs, from his uncle Anas ibn Malik, who said: There was a household from the Ansar who had a camel they used for irrigation. The camel became difficult for them and withheld its back from them. The Ansar came to the Messenger of Allah, peace and blessings of Allah be upon him, and said: "We had a camel we used for irrigation, but it has become difficult for us and has withheld its back from us, and the crops and palm trees have become thirsty." The Messenger of Allah, peace and blessings of Allah be upon him, said to his companions: "Rise." They rose, and he entered the garden while the camel was in a corner of it. The Prophet, peace and blessings of Allah be upon him, walked toward it. The Ansar said: "O Messenger of Allah, it has become like a mad dog, and we fear its assault upon you." He said: "There is no harm upon me from it." When the camel looked at the Messenger of Allah, peace and blessings of Allah be upon him, it approached him until it fell prostrate before him. The Messenger of Allah, peace and blessings of Allah be upon him, took hold of its forelock, and it was more submissive than it had ever been, until he put it back to work. His companions said to him: "O Prophet of Allah, this is a beast that does not reason, yet it prostrates to you, while we have reason; so we are more deserving to prostrate to you." He said: "It is not fitting for a human to prostrate to a human. If it were fitting for a human to prostrate to a human, I would have commanded the wife to prostrate to her husband because of the greatness of his right over her. By the One in Whose hand is my soul, if there were a sore from his foot to the parting of his head oozing with pus and blood, and she then approached it and licked it, she would not have fulfilled his right."