That is, "Allah enjoined the Israelites to refrain from murder because they were showing the same murderous symptoms as had been shown by the cruel son of Adam. That is why such strict checks on murder were applied." But the pity is that these precious instructions are not found in the present Bible. The Talmud, however, says, "To him who kills a single individual of Israel, it shall be reckoned as if he had slain the whole race and he who preserves a single individual of Israel, according to the Book of Allah, he preserves the whole world." It also says that a judge of the Israelites in a case of murder would warn the witness saying, "To him who kills a single individual of Israel, it shall be reckoned as if he has slain the whole race."
54This is to emphasize the sanctity of human life: it is essential for the preservation of human life that everyone should regard the life of the other as sacred and help to protect it. The one who takes the life of another without right does not commit injustice to that one alone, but also proves that he has no feeling for the sanctity of human life and of mercy for others. Hence, he is most surely the enemy of the whole human race, for if every individual suffered from the same kind of hard-heartedness, the whole human race would come to an end. On the contrary, if one helps to preserve a single human life, he is indeed a helper of all mankind for he possesses those qualities upon which the survival of the whole human race depends.
Tafsir Ibn-Kathir: Human Beings Should Respect the Sanctity of Other Human Beings
Allah says, because the son of Adam killed his brother in transgression and aggression, (كَتَبْنَا عَلَى بَنِى إِسْرَءِيلَ We ordained for the Children of Israel...) meaning, We legislated for them and informed them,
(أَنَّهُ مَن قَتَلَ نَفْساً بِغَيْرِ نَفْسٍ أَوْ فَسَادٍ فِى الاٌّرْضِ فَكَأَنَّمَا قَتَلَ النَّاسَ جَمِيعاً وَمَنْ أَحْيَـهَا فَكَأَنَّمَا أَحْيَا النَّاسَ جَمِيعاً that if anyone killed a person not in retaliation of murder, or (and) to spread mischief in the land - it would be as if he killed all mankind, and if anyone saved a life, it would be as if he saved the life of all mankind.) The Ayah states, whoever kills a soul without justification -- such as in retaliation for murder or for causing mischief on earth -- will be as if he has killed all mankind, because there is no difference between one life and another.
(وَمَنْ أَحْيَـهَا and if anyone saved a life...) by preventing its blood from being shed and believing in its sanctity, then all people will have been saved from him, so,
(فَكَأَنَّمَا أَحْيَا النَّاسَ جَمِيعاً it would be as if he saved the life of all mankind.) Al-A`mash and others said that Abu Salih said that Abu Hurayrah said, "I entered on `Uthman when he was under siege in his house and said, `I came to give you, my support. Now, it is good to fight (defending you) O Leader of the Faithful!' He said, `O Abu Hurayrah! Does it please you that you kill all people, including me' I said, `No.' He said, `If you kill one man, it is as if you killed all people. Therefore, go back with my permission for you to leave. May you receive your reward and be saved from the burden.' So I went back and did not fight.' `Ali bin Abi Talhah reported that Ibn `Abbas said, "It is as Allah has stated,
(مَن قَتَلَ نَفْساً بِغَيْرِ نَفْسٍ أَوْ فَسَادٍ فِى الاٌّرْضِ فَكَأَنَّمَا قَتَلَ النَّاسَ جَمِيعاً وَمَنْ أَحْيَـهَا فَكَأَنَّمَا أَحْيَا النَّاسَ جَمِيعاً if anyone killed a person not in retaliation of murder, or (and) to spread mischief in the land - it would be as if he killed all mankind, and if anyone saved a life, it would be as if he saved the life of all mankind.) Saving life in this case occurs by not killing a soul that Allah has forbidden. So, this is the meaning of saving the life of all mankind, for whoever forbids killing a soul without justification, the lives of all people will be saved from him.'' Similar was said by Mujahid;
(And if anyone saved a life...) means, he refrains from killing a soul. Al-`Awfi reported that Ibn `Abbas said that Allah's statement,
(فَكَأَنَّمَا قَتَلَ النَّاسَ جَمِيعاً it would be as if he killed all mankind. .) means, "Whoever kills one soul that Allah has forbidden killing, is just like he who kills all mankind.'' Sa`id bin Jubayr said, "He who allows himself to shed the blood of a Muslim, is like he who allows shedding the blood of all people. He who forbids shedding the blood of one Muslim, is like he who forbids shedding the blood of all people.'' In addition,
Ibn Jurayj said that Al-A`raj said that Mujahid commented on the Ayah, (فَكَأَنَّمَا قَتَلَ النَّاسَ جَمِيعاً it would be as if he killed all mankind,) "He who kills a believing soul intentionally, Allah makes the Fire of Hell his abode, He will become angry with him, and curse him, and has prepared a tremendous punishment for him, equal to if he had killed all people, his punishment will still be the same.''
Ibn Jurayj said that Mujahid said that the Ayah, (وَمَنْ أَحْيَـهَا فَكَأَنَّمَا أَحْيَا النَّاسَ جَمِيعاً and if anyone saved a life, it would be as if he saved the life of all mankind.) means, "He who does not kill anyone, then the lives of people are safe from him.''
Warning Those who Commit Mischief: Allah said, (وَلَقَدْ جَآءَتْهُمْ رُسُلُنَا بِالّبَيِّنَـتِAnd indeed, there came to them Our Messengers with Al-Bayyinat,) meaning, clear evidences, signs and proofs,
(ثُمَّ إِنَّ كَثِيراً مِّنْهُمْ بَعْدَ ذلِكَ فِى الاٌّرْضِ لَمُسْرِفُونَ even then after that many of them continued to exceed the limits in the land!) This Ayah chastises and criticizes those who commit the prohibitions, after knowing that they are prohibited from indulging in them. The Jews of Al-Madinah, such as Banu Qurayzah, An-Nadir and Qaynuqa`, used to fight along with either Khazraj or Aws, when war would erupt between them during the time of Jahiliyyah. When these wars would end, the Jews would ransom those who were captured and pay the blood money for those who were killed. Allah criticized them for this practice in Surat Al-Baqarah,
﴿وَإِذْ أَخَذْنَا مِيثَـقَكُمْ لاَ تَسْفِكُونَ دِمَآءِكُمْ وَلاَ تُخْرِجُونَ أَنفُسَكُمْ مِّن دِيَـرِكُمْ ثُمَّ أَقْرَرْتُمْ وَأَنتُمْ تَشْهَدُونَ - ثُمَّ أَنتُمْ هَـؤُلاَءِ تَقْتُلُونَ أَنفُسَكُمْ وَتُخْرِجُونَ فَرِيقًا مِّنكُم مِّن دِيَـرِهِمْ تَظَـهَرُونَ علَيْهِم بِالإِثْمِ وَالْعُدْوَنِ وَإِن يَأْتُوكُمْ أُسَـرَى تُفَـدُوهُمْ وَهُوَ مُحَرَّمٌ عَلَيْكُمْ إِخْرَاجُهُمْ أَفَتُؤْمِنُونَ بِبَعْضِ الْكِتَـبِ وَتَكْفُرُونَ بِبَعْضٍ فَمَا جَزَآءُ مَن يَفْعَلُ ذلِكَ مِنكُمْ إِلاَّ خِزْىٌ فِي الْحَيَوةِ الدُّنْيَا وَيَوْمَ الْقِيَـمَةِ يُرَدُّونَ إِلَى أَشَدِّ الّعَذَابِ وَمَا اللَّهُ بِغَـفِلٍ عَمَّا تَعْمَلُونَ ﴾
(And (remember) when We took your covenant (saying): Shed not your (people's) blood, nor turn out your own people from their dwellings. Then, (this) you ratified and (to this) you bear witness. After this, it is you who kill one another and drive out a party of your own from their homes, assist (their enemies) against them, in sin and transgression. And if they come to you as captives, you ransom them, although their expulsion was forbidden to you. Then do you believe in a part of the Scripture and reject the rest Then what is the recompense of those who do so among you, except disgrace in the life of this world, and on the Day of Resurrection they shall be consigned to the most grievous torment. And Allah is not unaware of what you do.) [2:84-85]
Muhammad Asad Explanation:
This moral truth is among those to which the first sentence of verse {15} of this surah alludes [(5:15) People of the Book! Now Our Messenger has come to you: he makes clear to you a good many things of the Book which you were wont to conceal, and also passes over many things...], and its succinct formulation fully explains the reason why the story of Cain and Abel is mentioned in this context. The expression "We have ordained unto the children of Israel" does not, of course, detract from the universal validity of this moral: it refers merely to its earliest enunciation.
(And, indeed, there came unto them) I.e., to the followers of the Bible, both the Jews and the Christians.
(Our apostles with all evidence of the truth: yet, behold, notwithstanding all this, many of them go on committing all manner of excesses on earth) The present participle la-musrifun indicates their "continuously committing excesses" (i.e., crimes), and is best rendered as "they go on committing" them. In view of the preceding passages, these "excesses" obviously refer to crimes of violence and, in particular, to the ruthless killing of human beings.