Musnad Ahmad 26:644

'Abd al-Rahman narrated to us, from Sufyan, from Salamah, from 'Isa ibn 'Asim, from Zirr ibn Hubaysh, from 'Abdullah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Taking omens is shirk (polytheism), taking omens is shirk." "But Allah, the Almighty and Majestic, removes it through reliance (tawakkul) upon Him."