Allah told them to hit the murdered man with a piece of the cow which they had been told to sacrifice. He would then bring him to life to tell them who the murderer was. They did this and he told them who had killed him. As this man was brought back to life by Allah, so will He bring the dead back to life on the Day of Judgement. Allah gives humanity clear signs of His power, to make them reflect and understand, and have true faith in Him.
And (remember) when you killed a man and disagreed among yourselves as to the crime. But Allah brought forth that which you were Taktumun (72)So We said: "Strike him (the dead man) with a piece of it (the cow)." Thus Allah brings the dead to life and shows you His Ayat (proofs, evidences, etc.) so that you may understand (73)
Bringing the murdered Man back to Life
Al-Bukhari said that,
فَادَّارَأْتُمْ فِيهَا
(And disagreed among yourselves as to the crime) means, "Disputed."
This is also the Tafsir of Mujahid. 'Ata' Al-Khurasani and Ad-Dahhak said, "Disputed about this matter." Also, Ibn Jurayj said that,
وَإِذْ قَتَلْتُمْ نَفْسًا فَادَّارَأْتُمْ فِيهَا
(And (remember) when you killed a man and disagreed among yourselves as to the crime) means, some of them said, "You killed him," while the others said, "No you killed him." This is also the Tafsir of 'Abdur-Rahman bin Zayd bin Aslam. Mujahid said that,
وَاللَّهُ مُخْرِجٌ مَّا كُنتُمْ تَكْتُمُونَ
(But Allah brought forth that which you were Taktumun) means, "what you were hiding."
Allah said,
فَقُلْنَا اضْرِبُوهُ بِبَعْضِهَا
(So We said: "Strike him (the dead man) with a piece of it (the cow)") meaning, "any part of the cow will produce the miracle (if they struck the dead man with it)." We were not told which part of the cow they used, as this matter does not benefit us either in matters of life or religion. Otherwise, Allah would have made it clear for us. Instead, Allah made this matter vague, so this is why we should leave it vague. Allah's statement,
كَذَٰلِكَ يُحْيِي اللَّهُ الْمَوْتَىٰ
(Thus Allah brings the dead to life) means, "They struck him with it, and he came back to life." This Ayah demonstrates Allah's ability in bringing the dead back to life. Allah made this incident proof against the Jews that the Resurrection shall occur, and ended their disputing and stubbornness over the dead person.
Allah mentioned His bringing the dead back to life in five instances in Surat Al-Baqarah. First Allah said,
ثُمَّ بَعَثْنَاكُم مِّن بَعْدِ مَوْتِكُمْ
(Then We raised you up after your death). He then mentioned the story about the cow. Allah also mentioned the story of those who escaped death in their land, while they were numbering in the thousands. He also mentioned the story of the Prophet who passed by a village that was destroyed, the story of Abraham and the four birds, and the land that comes back to life after it has died. All these incidents and stories alert us to the fact that bodies shall again become whole, after they were rotten. The proof of Resurrection is also reiterated in Allah's statement,
وَآيَةٌ لَّهُمُ الْأَرْضُ الْمَيْتَةُ أَحْيَيْنَاهَا وَأَخْرَجْنَا مِنْهَا حَبًّا فَمِنْهُ يَأْكُلُونَ - وَجَعَلْنَا فِيهَا جَنَّاتٍ مِّن نَّخِيلٍ وَأَعْنَابٍ وَفَجَّرْنَا فِيهَا مِنَ الْعُيُونِ - لِيَأْكُلُوا مِن ثَمَرِهِ وَمَا عَمِلَتْهُ أَيْدِيهِمْ أَفَلَا يَشْكُرُونَ
(And a sign for them is the dead land. We give it life, and We bring forth from it grains, so that they eat thereof. And We have made therein gardens of date palms and grapes, and We have caused springs of water to gush forth therein. So that they may eat of the fruit thereof ـ and their hands made it not. Will they not then give thanks?)(36:33-35).
The murderer had his supporters who wanted to hide his crime, and hence began accusing different people. But Allah willed that the criminal should be brought to book, and appointed a miraculous way of identifying him -- that is, the dead body of the murdered man should be touched with a part of the flesh of the sacrificial cow. When this was done, the dead man came back to life, announced the name of his murderer, and died again.
This miraculous event is a manifestation of the omnipotence of Allah, and Holy Qur'an presents it as an argument against those who deny the Resurrection of the dead for the Last Judgment. Verse 73 says that this precedent should induce people to make use of their reason, and see that what has happened in a past instance can as easily happen in a future instance.
With regard to this event one may ask as to why Allah made the resurrection of the dead man depend upon his being touched with a part of flesh when he had the power to bring the man back to life without the intervention of any such device; or, one may ask as to why the dead man should have been brought back to life when the name of the murderer could have been revealed even otherwise. In answer to this, we shall say that Allah is omnipotent, and does not act under any kind of compulsion, but that all His actions proceed from His all-embracing wisdom. Moreover, it is He alone who knows, and can know, the raison d'etre of what He does. The Shari'ah does not oblige us to discover the raison d'etre of each and every divine act, nor is it necessary or possible that we should be able to comprehend the raison d'etre in each case. The best way in such a case is to accept what Allah or the Holy Prophet ﷺ has said, and to keep quiet.
Let us say a word about the arrangement and sequence of the events. Verse 72 relates how a man was murdered, and how people started accusing each other. This is the beginning of the story which has been related earlier in Verses 67-71. This chronological order has not been preserved in the narration, but inverted, and this re-arrangement has a subtle significance. This long section of the Surah (Chapter) has been dealing with the transgressions of the Israelites, and this is just what the Holy Qur'an intends to bring out in narrating different stories, the narrating of stories not being an object in itself here. The present story is meant to show two misdeeds - firstly, committing a murder and then trying to hide it; secondly, raising uncalled-for objections to divine commandments. If the chronological order had been kept up, the readers would have supposed that it was only the first of these that was really intended, while the second was added only by way of completing the story. The present arrangement clearly shows that both the misdeeds have been equally emphasized.
Injunctions and related consideration
In this incident the statement of the murdered man was considered evidence for condemning the murderer, because Allah had informed Sayyidna Musa (علیہ السلام) through revelation that the man would, on coming back to life, speak the truth. Otherwise, one cannot be declared as being guilty of murder without proper evidence, the rules of which have been laid down by the Shari'ah.
A murder was committed among the Israelites in Moses’ time. The method that God revealed to His prophet to identify the killer was that an animal should be sacrificed, and the dead man’s corpse be struck with a piece of it. The dead man would then name the murderer. The third lesson in this instance was that life after death is no less a reality than life before death. Just as the dead corpse was revived, so every soul will be raised up in the Hereafter and given new life.