Allah mentioned the stubbornness of the Children of Israel and the many unnecessary questions they asked their Messengers. This is why when they were stubborn, Allah made the decisions difficult for them. Had they slaughtered a cow, any cow, it would have been sufficient for them, as Ibn `Abbas and `Ubaydah have said. Instead, they made the matter difficult, and this is why Allah made it even more difficult for them. They said,
﴿ ٱدۡعُ لَنَا رَبَّكَ يُبَيِّن لَّنَا مَا هِىَ ﴾
(Call upon your Lord for us that He may make plain to us what it is!), meaning, "What is this cow and what is its description'' Musa said,
﴿ إِنَّهُ ۥ يَقُولُ إِنَّہَا بَقَرَةٌ۬ لَّا فَارِضٌ۬ وَلَا بِكۡرٌ ﴾
(He says, `Verily, it is a cow neither too old nor too young'), meaning, that it is neither old nor below the age of breeding. This is the opinion of Abu Al-`Aliyah, As-Suddi, Mujahid, `Ikrimah, `Atiyah Al-`Awfi, `Ata', Al-Khurasani, Wahb bin Munabbih, Ad-Dahhak, Al-Hasan, Qatadah and Ibn `Abbas. Ad-Dahhak reported that Ibn `Abbas said that,
﴿ عَوَانُۢ بَيۡنَ ذَٲلِكَۖ ﴾
(But (it is) between the two conditions) means, "Neither old nor young. Rather, she was at the age when the cow is strongest and fittest.'' In his Tafsir Al-`Awfi reported from Ibn `Abbas that,
﴿ فَاقِعٌ۬ لَّوۡنُهَا ﴾
(bright in its colour) "A deep yellowish white.''
﴿ تَسُرُّ ٱلنَّـٰظِرِينَ ﴾
(pleasing the beholder) meaning, that it pleases those who see it. This is also the opinion of Abu Al-`Aliyah, Qatadah and Ar-Rabi` bin Anas. Furthermore, Wahb bin Munabbih said, "If you look at the cow's skin, you will think that the sun's rays radiate through its skin.'' The modern version of the Tawrah mentions that the cow in the Ayah was red, but this is an error. Or, it might be that the cow was so yellow that it appeared blackish or reddish in color. Allah's knows best.
﴿ إِنَّ ٱلۡبَقَرَ تَشَـٰبَهَ عَلَيۡنَا ﴾
(Verily, to us all cows are alike) this means, that since cows are plentiful, then describe this cow for us further,
﴿ وَإِنَّآ إِن شَآءَ ٱللَّهُ ﴾
(And surely, if Allah wills) and if you further describe it to us,
﴿ لَمُهۡتَدُونَ ﴾
﴿ قَالَ إِنَّهُ ۥ يَقُولُ إِنَّہَا بَقَرَةٌ۬ لَّا ذَلُولٌ۬ تُثِيرُ ٱلۡأَرۡضَ وَلَا تَسۡقِى ٱلۡحَرۡثَ ﴾
(He says, `It is a cow neither trained to till the soil nor water the fields') meaning, it is not used in farming, or for watering purposes. Rather, it is honorable and fair looking. `Abdur-Razzaq said that Ma`mar said that Qatadah said that,
﴿ مُّسَلَّمَةٌ ﴾
(sound) means, "The cow does not suffer from any defects.'' This is also the opinion of Abu Al-`Aliyah and Ar-Rabi`. Mujahid also said that the Ayah means the cow is free from defects. Further, `Ata' Al-Khurasani said that the Ayah means that its legs and body are free of physical defects.
Also, Ad-Dahhak said that Ibn `Abbas said that the Ayah,
﴿ فَذَبَحُوهَا وَمَا كَادُواْ يَفۡعَلُونَ ﴾
(So they slaughtered it though they were near to not doing it) means, "They did not want to slaughter it.''
This means that even after all the questions and answers about the cow's description, the Jews were still reluctant to slaughter the cow. This part of the Qur'an criticized the Jews for their behavior, because their only goal was to be stubborn, and this is why they nearly did not slaughter the cow. Also, `Ubaydah, Mujahid, Wahb bin Munabbih, Abu Al-`Aliyah and `Abdur-Rahman bin Zayd bin Aslam said, "The Jews bought the cow with a large amount of money.'' There is a difference of opinion over this.
﴿ وَإِذۡ قَتَلۡتُمۡ نَفۡسً۬ا فَٱدَّٲرَٲٔۡتُمۡ فِيہَاۖ وَٱللَّهُ مُخۡرِجٌ۬ مَّا كُنتُمۡ تَكۡتُمُونَ • فَقُلۡنَا ٱضۡرِبُوهُ بِبَعۡضِہَاۚ كَذَٲلِكَ يُحۡىِ ٱللَّهُ ٱلۡمَوۡتَىٰ وَيُرِيڪُمۡ ءَايَـٰتِهِۦ لَعَلَّكُمۡ تَعۡقِلُونَ ﴾
(72. And (remember) when you killed a man and disagreed among yourselves as to the crime. But Allah brought forth that which you were Taktumun.) (73. 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.)