Musnad Ahmad 25:542

Hassan ibn Musa narrated to us, Hammad ibn Salamah narrated to us, from Ammar ibn Abi Ammar, from Ibn Abbas, and Thabit al-Bunani, from Anas ibn Malik: That the Messenger of Allah, peace and blessings of Allah be upon him, used to deliver the sermon leaning against a palm tree trunk. When the pulpit was made for him, he moved to the pulpit. The trunk moaned until the Messenger of Allah, peace and blessings of Allah be upon him, came to it and embraced it, so it became quiet. The Messenger of Allah, peace and blessings of Allah be upon him, said: "Had I not embraced it, it would have moaned until the Day of Resurrection."