Qur'an 5:32

مِنْ أَجْلِ ذَٰلِكَ كَتَبْنَا عَلَىٰ بَنِىٓ إِسْرَٰٓءِيلَ أَنَّهُۥ مَن قَتَلَ نَفْسًۢا بِغَيْرِ نَفْسٍ أَوْ فَسَادٍ فِى ٱلْأَرْضِ فَكَأَنَّمَا قَتَلَ ٱلنَّاسَ جَمِيعًا وَمَنْ أَحْيَاهَا فَكَأَنَّمَآ أَحْيَا ٱلنَّاسَ جَمِيعًا ۚ وَلَقَدْ جَآءَتْهُمْ رُسُلُنَا بِٱلْبَيِّنَـٰتِ ثُمَّ إِنَّ كَثِيرًا مِّنْهُم بَعْدَ ذَٰلِكَ فِى ٱلْأَرْضِ لَمُسْرِفُونَ

For that cause We decreed for the Children of Israel that whosoever killeth a human being for other than manslaughter or corruption in the earth, it shall be as if he had killed all mankind, and whoso saveth the life of one, it shall be as if he had saved the life of all mankind. Our messengers came unto them of old with clear proofs (of Allah's Sovereignty), but afterwards lo! many of them became prodigals in the earth.