Sahih Bukhari

Narrated `Abdullah:I asked Allah's Messenger (ﷺ) ""What is the biggest sin in the sight of Allah?"" He said, ""To set up rivals unto Allah though He alone created you."" I said, ""In fact, that is a tremendous sin,"" and added, ""What next?"" He said, ""To kill your son being afraid that he may share your food with you."" I further asked, ""What next?"" He said, ""To commit illegal sexual intercourse with the wife of your neighbor