Musnad Ahmad 31:791

Yazid narrated to us, al-Qasim ibn al-Fadl al-Haddani informed us, from Abu Nadra, from Abu Sa’id al-Khudri, who said: A wolf attacked a sheep and took it, so the shepherd pursued it and snatched it away from it. The wolf sat back on its tail and said: "Do you not fear Allah? You snatch from me a provision that Allah has driven to me." The shepherd said: "How amazing! A wolf sitting on its tail, speaking to me with the speech of humans!" The wolf said: "Shall I not inform you of something more amazing than that? Muhammad, may Allah bless him and grant him peace, is in Yathrib, informing the people of the news of what has already passed." The shepherd then came driving his sheep until he entered Medina, and he gathered them into one of its corners. Then he came to the Messenger of Allah, may Allah bless him and grant him peace, and informed him. The Messenger of Allah, may Allah bless him and grant him peace, ordered that it be announced: "Prayer is a gathering," and then he went out and said to the shepherd: "Inform them." So he informed them. The Messenger of Allah, may Allah bless him and grant him peace, said: "He has spoken the truth. By the One in Whose hand is my soul, the Hour will not be established until wild beasts speak to humans, and a man’s whip-tip speaks to him, and his sandal-strap, and his thigh informs him of what his family did after him."