According to the Law almost everything is purified by blood, and without the shedding of blood there is no forgiveness.
What is it that constitutes the essence of religious worship? It is sacrifice.
The point of religion is not to make men moral or to make society just, not to foster community or even to win eternal life. The point of religion is to glorify God. The religious man knows that he has duties to God. First, he owes God gratitude for creating him. Second, he reveres God because this is the just response to God’s intrinsic goodness—to His ontological grandeur as the perfect and unlimited being and to His moral beauty as seen in His generosity and mercy (and, Christians would add, as being Himself a community of love). Of course, the religious man doesn’t just experience God as a good Thing to be approved; he experiences God as holy. Those things which are consecrated to Him are sacred things, and profane things seem impure in His holy presence.
How does man do his duty to God? One way is to care for His creatures, most especially by showing love and justice to other people; a kindness done for them is done also for their Creator. However, this is not the only, or even always the primary way that a man discharges his duty to God. A man’s purpose is not fulfilled by his service to finite goods. True, a man can occupy his whole life in service of his family or his country, or to advance knowledge or social causes, but the horizon of his mind is larger than these things. In understanding the world, his mind ascends from effect to cause, not resting until it reaches the First Cause, the Necessary Being. In justifying moral duties, the mind ascends from means to ends, from relative goods to absolute Good, from delegated authority to its ultimate Source. This infinite horizon of the mind causes men to desire a direct a relationship with God, something in addition to the implicit contacts with Him given by relationships to His creatures. The religious man craves God’s presence. He desires sacred spaces (“holy ground”) so that he can physically face God. He wishes to make offerings to God, both to express his devotion and to draw closer to the Divinity. The offering of goods establishes a new bond with the Creator, and those things which are offered to God thereby become sacred objects, that is, conduits which mediate the divine presence. The sacrifices a man offers represent himself—they express his desire to offer himself to God and thereby to become holy, to be a thing consecrated to God.