Abbas - Tanwîr al-Miqbâs min Tafsîr Ibn ‘Abbâs
(And We said: Smite him) the murdered person (with some of it) with an organ of the cow; and it is also said: with its tail or tongue. (Thus) just as He brought 'Amil back to life (Allah bringeth the dead to life) for the Resurrection (and showeth you His portents) bringing the dead to life (so that ye may understand) in order that you may believe in resurrection after death.
so We said, ‘Smite him, the slain man, with part of it’, and so when he was struck with its tongue or its tail, he came back to life and said, ‘So-and-so killed me’, and after pointing out two of his cousins, he died; the two [killers] were denied the inheritance and were later killed. God says: even so, is the revival, for, God brings to life the dead, and He shows you His signs, the proofs of His power, so that you might understand, [that you might] reflect and realise that the One capable of reviving a single soul is also capable of reviving a multitude of souls, and then believe.
So We said, 'Smite him with part of it', with its tail or its tongue, according to what is recounted in the story, so that he might come back to life and inform you of the [identity of his] killer. The smiting [of him] with the tail is alludes to rendering the soul dead while keeping alive its weakest and last faculties and that aspect [of it] that adjoins the vegetative soul and constitutes a link with it, such as the sense of touch, for example, and all of the external senses, namely, its [the cow's] tail. The smiting [of the dead man] with the tongue alludes to the rectification of its character traits and its faculties, while keeping alive its [faculty of] reflection, namely, its tongue. Both of these [smitings] represent two paths: [the first is] the path of spiritual discipline and the mortification of wrath and lust, as is the way of the Sufi, [a path] which is more befitting of those powerful criminal souls of conquest and transgression' [the second is] the path of securing and rectifying character traits, which is the way of the scholars and the sages and which is more befitting of those weak souls and those that are pure and easily-led. They smote him and he rose, the blood gushing forth from his veins, and he informed them of [the identity of] his killers, in other words, he became alive subsisting through true life while the traces of the killing were on him because of his attachment to the body and his being polluted by his demands according to necessity. And he came to know the state of the corporeal powers in preventing him from perceiving and their veiling of him from his light. Thus God brings to life the dead, in other words, in the manner of that tremendous bringing back to life does God bring to life those who are dead through their ignorance of true practical life; and He shows you [His signs], His proofs and the signs of His attributes, so that you might understand.
(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 فَادَرَأْتُمْ 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.''
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,
كَذَلِكَ يُحْىِ اللَّهُ الْمَوْتَى
(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 بَعَثْنَـكُم 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,
(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).
Maududi - Sayyid Abul Ala Maududi - Tafhim al-Qur'an
The wording of the Qur'an clearly shows that the murdered man came to life for a little while and told the name of his murderer. However, there is some ambiguity concerning the method applied for discovering the murderer, that is, the striking of the dead body of the murdered man with a piece of "the sacrificed cow". A method similar to this described in Deut. 21: 1-9, confirms the interpretation put forward by the ancient scholars, that is, the dead body was struck with a piece of the flesh of the sacrificed cow and it came to life. In this way, a Sign of Allah was shown and at the same time it was demonstrated that the object of their worship was so powerless that its slaughter did not cause any harm. On the contrary, its slaughter proved useful.
so We said “Smite him with part of it”; God brings to life the dead and He shows you His signs so that you might understand. God سبحانه wanted to give life to the dead man so that he could expose his killer through the testimony [of the slain] so He commanded them to kill one of their animals and made it the cause of bringing the slain man to life. The allusion here is to anyone who desires the life of his heart; he will only attain it by sacrificing his lower self since the heart of anyone who sacrifices his lower self through struggle mujāhadāt comes to life by the lights of witnessing mushāhadāt. Likewise when God wants someone's reputation to live forever He causes his reputation in this world to pass into obscurity.