Musnad Ahmad 26:481

Ibn Numayr narrated to us, al-A‘mash narrated to us, from Ibrahim, from ‘Alqamah, from ‘Abdullah, who said: When this verse was revealed: "Those who believe and do not mix their belief with injustice" [al-An‘am: 82], they said: "O Messenger of Allah, which of us does not wrong himself?" He said: "It is not that; it is polytheism (shirk). Have you not heard what Luqman said to his son: 'Do not associate partners with Allah; indeed, associating partners with Allah is a great injustice' [Luqman: 13]?"