Sahih al-Bukhari Book 65, Hadith 283
I or somebody, asked Allah's Messenger (ﷺ) "Which is the biggest sin in the Sight of Allah?" He said, "That
you set up a rival (in worship) to Allah though He Alone created you." I asked, "What is next?" He
said, "Then, that you kill your son, being afraid that he may share your meals with you." I asked,
"What is next?" He said, "That you commit illegal sexual intercourse with the wife of your neighbor."
Then the following Verse was revealed to confirm the statement of Allah's Messenger (ﷺ):
"Those who invoke not with Allah, any other god, nor kill life as Allah has forbidden except for just
cause, nor commit illegal sexual intercourse." (25.68)
A man said, "O Allah's Prophet! Will Allah gather the non-believers on their faces on the Day of Resurrection?" He said, "Will not the One Who made him walk on his feet in this world, be able to make him walk on his face on the Day of Resurrection?" (Qatada, a subnarrator, said: Yes, By the Power of Our Lord!)
That he asked Sa`id bin Jubair, "Is there any repentance of the one who has murdered a believer intentionally?" Then I recited to him:-- "Nor kill such life as Allah has forbidden except for a just cause." Sa`id said, "I recited this very Verse before Ibn `Abbas as you have recited it before me. Ibn `Abbas said, 'This Verse was revealed in Mecca and it has been abrogated by a Verse in Surat-An-Nisa which was later revealed in Medina."