It was narrated that 'Abdullah (رضي الله عنه) said:

When this verse was revealed, “It is those who believe (in the Oneness of Allah and worship none but Him Alone) and confuse not their Belief with Zulm, (wrong, i.e. by worshipping others besides Allah)" (al-An'am 6:82), it was hard on the people and they said: O Messenger of Allah, who among us does not wrong himself? He said: “It is not what you think. Have you not heard what the righteous slave said: ‘O my son! Join not in worship others with Allah. Verily, joining others in worship with Allah is a great Zulm (wrong) indeed’ (Luqman 31:13)? Rather it refers to shirk."