The two sons of Adam each offered a sacrifice to Allah. It was accepted from one and not from the other. The one whose offering was not accepted, burning with envy, said: I will kill you.
The other answered calmly: Allah accepts only from those who are mindful of Him. And he said: even if you stretch out your hand to kill me, I will not stretch out mine to kill you — I fear Allah, Lord of the worlds.
Yet his soul urged him to kill his brother, and he killed him, and became one of the losers.
Then, not knowing what to do with the body, he saw a crow that Allah sent, scratching the ground, to show him how to cover his brother's body. He cried: woe to me! Could I not even be like this crow? And he became full of regret.
مِنۡ أَجۡلِ ذَٰلِكَ كَتَبۡنَا عَلَىٰ بَنِيٓ إِسۡرَٰٓءِيلَ أَنَّهُۥ مَن قَتَلَ نَفۡسَۢا بِغَيۡرِ نَفۡسٍ أَوۡ فَسَادٖ فِي ٱلۡأَرۡضِ فَكَأَنَّمَا قَتَلَ ٱلنَّاسَ جَمِيعٗا وَمَنۡ أَحۡيَاهَا فَكَأَنَّمَآ أَحۡيَا ٱلنَّاسَ جَمِيعٗاۚ وَلَقَدۡ جَآءَتۡهُمۡ رُسُلُنَا بِٱلۡبَيِّنَٰتِ ثُمَّ إِنَّ كَثِيرٗا مِّنۡهُم بَعۡدَ ذَٰلِكَ فِي ٱلۡأَرۡضِ لَمُسۡرِفُونَ
“Because of that, We decreed upon the Children of Israel that whoever kills a soul unless for a soul or for corruption [done] in the land - it is as if he had slain mankind entirely. And whoever saves one - it is as if he had saved mankind entirely. And Our messengers had certainly come to them with clear proofs. Then indeed many of them, [even] after that, throughout the land, were transgressors.”
Surah Al-Ma'idah 5:32
Translation: Saheeh International (QuranEnc)