Musnad Abu Ya'la al-Mawsili 152:91

Abu Khaythama narrated to us, Jarir narrated to us, from al-A'mash, from Ibrahim, from 'Alqama, from 'Abdullah, who said: When this verse was revealed: "Those who believe and do not mix their belief with injustice," it was difficult for the companions of the Messenger of Allah (may Allah bless him and grant him peace), and they said: "Which of us has not mixed his belief with injustice?" The Messenger of Allah (may Allah bless him and grant him peace) said: "It is not that. Have you not heard the saying of Luqman: 'Indeed, polytheism is a great injustice'?"