Prophetic Commentary on the Qur'an (Tafseer of the Prophet (pbuh))
Bukhari :: Book 6 :: Volume 60 :: Hadith 153
Narrated Abdullah:
When:"...and confuse not their belief with wrong." (6.82) was revealed, the Prophet's companions said, "Which of us has not done wrong?" Then there was revealed:-- "Verily joining others in worship with Allah is a tremendous wrong indeed." (31.13)