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)

حَدَّثَنِي مُحَمَّدُ بْنُ بَشَّارٍ، حَدَّثَنَا ابْنُ أَبِي عَدِيٍّ، عَنْ شُعْبَةَ، عَنْ سُلَيْمَانَ، عَنْ إِبْرَاهِيمَ، عَنْ عَلْقَمَةَ، عَنْ عَبْدِ اللَّهِ ـ رضى الله عنه ـ قَالَ لَمَّا نَزَلَتْ وَلَمْ يَلْبِسُوا إِيمَانَهُمْ بِظُلْمٍ قَالَ أَصْحَابُهُ وَأَيُّنَا لَمْ يَظْلِمْ فَنَزَلَتْ إِنَّ الشِّرْكَ لَظُلْمٌ عَظِيمٌ