Sahih Bukhari Volume 009, Book 084, Hadith Number 053.
Narrated By 'Abdullah : When the Verse: 'It is those who believe and confuse not their belief with wrong (i.e., worshipping others besides Allah): (6.82) was revealed, it became very hard on the companions of the Prophet and they said, "Who among us has not confused his belief with wrong (oppression)?" On that, Allah's Apostle said, "This is not meant (by the Verse). Don't you listen to Luqman's statement: 'Verily! Joining others in worship with Allah is a great wrong indeed.' (31.13)