Hadith
حَدَّثَنِي إِسْحَاقُ، أَخْبَرَنَا عِيسَى بْنُ يُونُسَ، حَدَّثَنَا الأَعْمَشُ، عَنْ إِبْرَاهِيمَ، عَنْ عَلْقَمَةَ، عَنْ عَبْدِ اللَّهِ ـ رضى الله عنه ـ قَالَ لَمَّا نَزَلَتِ {الَّذِينَ آمَنُوا وَلَمْ يَلْبِسُوا إِيمَانَهُمْ بِظُلْمٍ} شَقَّ ذَلِكَ عَلَى الْمُسْلِمِينَ، فَقَالُوا يَا رَسُولَ اللَّهِ، أَيُّنَا لاَ يَظْلِمُ نَفْسَهُ قَالَ " لَيْسَ ذَلِكَ، إِنَّمَا هُوَ الشِّرْكُ، أَلَمْ تَسْمَعُوا مَا قَالَ لُقْمَانُ لاِبْنِهِ وَهْوَ يَعِظُهُ {يَا بُنَىَّ لاَ تُشْرِكْ بِاللَّهِ إِنَّ الشِّرْكَ لَظُلْمٌ عَظِيمٌ }".
Narrated `Abdullah:When the Verse:-- 'Those who believe and mix not their belief with wrong.' was revealed, the Muslims felt it very hard on them and said, "O Allah's Messenger (ﷺ)! Who amongst us does not do wrong to himself?" He replied, "The Verse does not mean this. But that (wrong) means to associate others in worship to Allah: Don't you listen to what Luqman said to his son when he was advising him," O my son! Join not others in worship with Allah. Verily joining others in worship with Allah is a great wrong indeed
Sahih
Sahih al-Bukhari 3429 ·Book 60, Hadith 100·Also available on sunnah.com·