Musnad Ahmad 847:5

Yahya ibn Sa'id narrated to us, al-Taymi narrated to us, from Abu 'Uthman, from Qabisah ibn Mukhariq and Zuhayr ibn 'Amr, they said: When {And warn your closest kindred} [Ash-Shu'ara: 214] was revealed, the Messenger of Allah, peace and blessings of Allah be upon him, climbed a mound of a mountain, upon its highest point was a rock. He began to call out: "O Banu 'Abd Manaf, I am only a warner. My likeness and your likeness is like a man who saw the enemy, so he went to watch over his family, fearing that they would be overtaken. So he began to call out and shout: 'O morning alarm!'"