I asked the Prophet, "What is the greatest sin in the Sight of Allah?" He said, "That you set up a rival unto Allah though He Alone created you." I said, "That is indeed a great sin." Then asked, "What is next?" He said, "To kill your son lest he should share your food with you." I asked, "What is next?" He said, "To commit illegal sexual intercourse with the wife of your neighbor." (Using translation from Bukhārī 4477)

سَأَلْتُ رَسُولَ اللَّهِ ﷺ أَيُّ الذَّنْبِ أَعْظَمُ؟ قَالَ «أَنْ تَجْعَلَ لِلَّهِ نِدًّا وَهُوَ خَلَقَكَ» قُلْتُ إِنَّ ذَلِكَ لَعَظِيمٌ ثُمَّ أَيُّ؟ قَالَ «أَنْ تَقْتُلَ وَلَدَكَ مَخَافَةَ أَنْ يَطْعَمَ مَعَكَ» قُلْتُ ثُمَّ أَيُّ؟ قَالَ «أَنْ تُزَانِيَ حَلِيلَةَ جَارِكَ»