Al-Ma'idah' - 5:32

مِنْ أَجْلِ ذَلِكَ كَتَبْنَا عَلَى بَنِي إِسْرَائِيلَ أَنَّهُ مَن قَتَلَ نَفْسًا بِغَيْرِ نَفْسٍ أَوْ فَسَادٍ فِي الأَرْضِ فَكَأَنَّمَا قَتَلَ النَّاسَ جَمِيعًا وَمَنْ أَحْيَاهَا فَكَأَنَّمَا أَحْيَا النَّاسَ جَمِيعًا وَلَقَدْ جَاءتْهُمْ رُسُلُنَا بِالبَيِّنَاتِ ثُمَّ إِنَّ كَثِيراً مِّنْهُم بَعْدَ ذَلِكَ فِي الأَرْضِ لَمُسْرِفُونَ
[5:32]
For this reason did We prescribe to the children of Israel that whoever slays a soul, unless it be for manslaughter or for mischief in the land, it is as though he slew all men; and whoever keeps it alive, it is as though he kept alive all men; and certainly Our messengers came to them with clear arguments, but even after that many of them certainly act extravagantly in the land.
On that account: We ordained for the Children of Israel that if any one slew a person - unless it be for murder or for spreading mischief in the land - it would be as if he slew the whole people: and if any one saved a life, it would be as if he saved the life of the whole people. Then although there came to them Our messengers with clear signs, yet, even after that, many of them continued to commit excesses in the land.
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.