Walbudna jaAAalnaha lakum min shaAAa-iri Allahi lakum feeha khayrun fathkuroo isma Allahi (surah Hajj: 36)

Tafseer Tafheem-ul-Quran by Syed Abu-al-A'la Maududi

(22:36) And We have included the camels *67 (dedicated for sacrifice) among the Symbols of Allah, for there is much good for you in them. *68 Therefore make them stand *69 and mention the name of Allah over them, *70 and when (after the sacrifice,) their backs lie still on the ground, *71 you may eat of their flesh and give of it to the contented ones and to those who ask for it. Thus have We subjected these animals to you so that you may be grateful' *72

Walbudna ja`alnaahaa lakum min sha`aaa`iril laahi lakum feehaa khairun fazkurusmal laahi `alaihaa sawaaff; fa izaa wajabat junoobuhaa fakuloo minhaa wa at`imul qaani`a walmu`tarr; kazaalika sakhkharnaahaa lakum la`allakum tashkuroon

*67) Seven persons can become partners in the sacrifice of one camel and likewise in the sacrifice of one cow and the like, as enjoined by the Holy Prophet in a Tradition reported by Jabir bin `Abdullah in the Collection of Hadith by Muslim.
*68) That is, "You should sacrifice animals because you get many benefits front them to show your gratitude to AIIah, the Giver, and also to acknowledge His Supremacy and Sovereignty".
*69) It should be noted that a camel is sacrificed while it is standing. This was enjoined by the Holy Prophet and is supported by Ibn `Abbas, Mujahid, I)ahhak, etc. Muslim and Bukhar have reported a Tradition from Hadrat Ibn Umar, who saw a man slaughtering his camel in the sitting position. He said to him, "Tie one foot of your camel and make it stand, because that is the way of Abul Qasim (peace be upon him)". According to a tradition reported by Hadrat Jabir bin 'Abdullah, in Abu Dawud, the Holy Prophet and his Companions would tie a left foot of the camel and would make it stand on three feet; then they would slaughter it. The same is implied by the subsequent sentence: " ...and after their backs lie still on the ground .......", i.e. when they fall down to the ground after enough of their blood has run out.
*70) "Mention the name of Allah over them" implies that animals should be slaughtered by pronouncing the name of Allah over them, because without that their flesh would be unlawful to eat. This shows that in the Islamic Law there is no conception of slaughtering an animal without pronouncing the name of Allah over it. According to Traditions, there are different wordings for pronouncing the name of Allah over the animals at the time of their slaughter. Some of these are:
(I) Bismillahi Allahu Akbar; Allahumma minks wa laka: "In the name of Allah, AIIah is most Great! O Allah, this is Thine and is presented to Thee".
(2) Allahu Akbar- La ilaha ill-Allahu; Allahumma minks wa laka: "Allah is most Great: There is no god but Allah: O Allah, this is Thine and is presented to Thee" .
(3) Inni wajjahtu wajhiya lillazi fatar-as-sama wati wal-arda, hanif-an-wa ma ana min-al-mushrikin. Inns Salati wa nusuki wa mahyaya wa mamati lillahi Rabb-il- 'alamin. La sharika lahu wa bi-zalika umirtu wa ana min-al-Muslimin. A llahumma minks wa laka. "I have turned my face sincerely towards the Being Who created the heavens and the earth, and I am not from among the idolatrous people. My Salat and my rites of worship and my life and my death are all for AIIah, the Lord of the universe, Who has no partner with Him. This is what I have been enjoined and I am the first to surrender to Him. O Allah! This is Thine, and is presented to Thee" .
*71) ".......lie still on the ground......." means till they die completely, for the Holy Prophet prohibited to cut off a piece of flesh, if there is still any sign of life in the slaughtered animal; if this is done, the piece of flesh would be unlawful.
*72) This is another reason why animals should be sacrificed: "They should be sacrificed as a mark of gratitude to Allah Who has subjected them to you".