Al-Bukhari said that,
(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,
﴿وَءَايَةٌ لَّهُمُ الاٌّرْضُ الْمَيْتَةُ أَحْيَيْنَـهَا وَأَخْرَجْنَا مِنْهَا حَبّاً فَمِنْهُ يَأْكُلُونَ - وَجَعَلْنَا فِيهَا جَنَّـتٍ مِّن نَّخِيلٍ وَأَعْنَـبٍ وَفَجَّرْنَا فِيهَا مِنَ الْعُيُونِ - لِيَأْكُلُواْ مِن ثَمَرِهِ وَمَا عَمِلَتْهُ أَيْدِيهِمْ أَفَلاَ 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).
﴿ثُمَّ قَسَتْ قُلُوبُكُمْ مِّن بَعْدِ ذلِكَ فَهِىَ كَالْحِجَارَةِ أَوْ أَشَدُّ قَسْوَةً وَإِنَّ مِنَ الْحِجَارَةِ لَمَا يَتَفَجَّرُ مِنْهُ الأَنْهَـرُ وَإِنَّ مِنْهَا لَمَا يَشَّقَّقُ فَيَخْرُجُ مِنْهُ الْمَآءُ وَإِنَّ مِنْهَا لَمَا يَهْبِطُ مِنْ خَشْيَةِ اللَّهِ وَمَا اللَّهُ بِغَـفِلٍ عَمَّا تَعْمَلُونَ ﴾
(74. Then after that your hearts were hardened and became as stones or even worse in hardness. And indeed, there are stones out of which rivers gush forth, and indeed, there are of them (stones) which split asunder so that water flows from them, and indeed, there are of them (stones) which fall down for fear of Allah. And Allah is not unaware of what you do.)