Sahih al-Bukhari 7532
Narrated `Abdullah:
A man said, "O Allah's Messenger (ﷺ)! Which sin is the biggest in Allah's Sight?" The Prophet (ﷺ) said, "To set 
up rivals unto Allah though He Alone created you." That man said, "What is next?" The Prophet (ﷺ) said, 
"To kill your son lest he should share your food with you.'' The man said, "What is next?" The 
Prophet said, "To commit illegal sexual intercourse with the wife of your neighbor." Then Allah 
revealed in confirmation of that: "And those who invoke not with Allah any other god, nor kill such 
life as Allah has made sacred except for just cause, nor commit illegal sexual intercourse and whoever 
does this shall receive the punishment..... (25.68)
حَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، حَدَّثَنَا جَرِيرٌ، عَنِ الأَعْمَشِ، عَنْ أَبِي وَائِلٍ، عَنْ عَمْرِو بْنِ شُرَحْبِيلَ، قَالَ قَالَ عَبْدُ اللَّهِ قَالَ رَجُلٌ يَا رَسُولَ اللَّهِ أَىُّ الذَّنْبِ أَكْبَرُ عِنْدَ اللَّهِ قَالَ ‏"‏ أَنْ تَدْعُوَ لِلَّهِ نِدًّا، وَهْوَ خَلَقَكَ ‏"‏‏.‏ قَالَ ثُمَّ أَىّ قَالَ ‏"‏ ثُمَّ أَنْ تَقْتُلَ وَلَدَكَ، أَنْ يَطْعَمَ مَعَكَ ‏"‏‏.‏ قَالَ ثُمَّ أَىّ قَالَ ‏"‏ أَنْ تُزَانِيَ حَلِيلَةَ جَارِكَ ‏"‏‏.‏ فَأَنْزَلَ اللَّهُ تَصْدِيقَهَا ‏{‏وَالَّذِينَ لاَ يَدْعُونَ مَعَ اللَّهِ إِلَهًا آخَرَ وَلاَ يَقْتُلُونَ النَّفْسَ الَّتِي حَرَّمَ اللَّهُ إِلاَّ بِالْحَقِّ وَلاَ يَزْنُونَ وَمَنْ يَفْعَلْ ذَلِكَ‏}‏ الآيَةَ‏.‏