Jesus came to teach humans that true sacrifice does not consist in offering God something outside of ourselves: fruits, flour or livestock, and so on, as was the custom at that time. Because even if the offering of products of the earth or of animals shows a will to give something up, the sacrifice is still not as essential as giving up the satisfaction of certain appetites or lusts.
Jesus thus came to teach us to sacrifice our inner animals; yes, because our lower nature is the lair of all animals, both wild and domestic. We must sacrifice the animals that are our vices: egoism, jealousy, hatred and sensuality.
From the sacrifice of burning them on our inner altar, energies will be released which we will be able to put at the service of the spirit, the Deity.