Musnad Abu Ya'la al-Mawsili 152:151

Waki' narrated to us, from Sufyan, from Salamah ibn Kuhayl, from Isa ibn Asim al-Asadi, from Zirr, from Abdullah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Taking omens is shirk (polytheism), and there is not one of us but [it occurs in his heart], but Allah removes it through reliance (tawakkul) upon Him."