Fiqh-us-Sunnah Volume 5, Hajj and ‘Umrah, Fiqh 5.109B.

Section : Sacrificial Animals.

These are animals brought to the Haram, the Sacred Mosque, seeking the closeness and pleasure of Allah, Who says in the Qur’an (22.36), “The sacrificial camels We have made for you as among the symbols from Allah: in them is (much) good for you: then pronounce the name of Allah over them as they line up (for sacrifice) when they are down on their sides (after slaughter), eat you thereof, and feed such as beg with due humility: thus have We made animals subject to you, that you may be grateful. It is not their meat nor their blood, that reaches Allah: it is your piety that reaches Him.”

‘Umar said, “Sacrifice animals, for Allah loves sacrifice. The Prophet (peace be upon him) offered one hundred camels in sacrifice for the pleasure of Allah.” This offering by him was supererogatory.