A sacrifice is a special kind of gift-offering, addressed to God, our Creator and Last End.
1. In ordinary life we offer gifts to those we love or respect, as a sign of our affection or admiration or reverence, and as a means of establishing or strengthening friendly relations with them. In this way, for instance, we give Christmas and birthday presents.
In their relations with the Divinity, men have spontaneously adopted a similar practice. God is our Creator, the Giver of all good things, and He is our Last End in whom alone we can find fulfillment and happiness. Men offer Him gifts from among the things they have received from Him, in order to acknowledge Him as the Creator and Giver of all things. A gift thus offered to God becomes sacred, the offering of it is called a sacrifice.
2. From the very beginning men have acknowledged God’s supremacy by offering sacrifice. The essence of the sacrifice is a rite which signifies the transfer of the gift into the immediate possession of the Divinity. And since God is invisible, He is represented by the altar which receives the offering: gifts are placed on it, the life-blood of animals is poured on it; the offering is sometimes burned on the altar, as part of the symbolism: it is given up to God.
Because men have always felt their sinfulness and their unworthiness to approach God, they have offered their sacrifices through the intermediary of priests, men specially consecrated and set aside for the service of God.
3. Men have often offered the most valuable animals of their flocks. God, of course, does not need anything, and all we have is His. He does not seek our possessions, but ourselves, our free love and self-surrender, and this is what the exterior sacrifice signifies: the oblation of the gift is a symbol of our interior sacrifice, of the adoration and love by which the soul gives itself completely to its Creator. Without this interior sacrifice the exterior offering is meaningless, insincere, and cannot be pleasing to God. What matters therefore is not so much the value of the gift as the sincerity of the giver’s self-gift.
Self-oblation is the finest and most complete expression of true religion; its intensity measures the quality and depth of a man’s religious attitude.
Giving requires giving up something. Sincere self-oblation to God implies that we mean to give up self-seeking, to seek God’s will and pleasure rather than our own will and satisfaction. Sacrifice is something great and difficult.
In common language we speak of making sacrifices for a person or a cause, of a mother sacrificing herself for her children. The meaning is that something valuable–time, luxuries, health, life itself–is given up for another, for love of him.
4. The offering of sacrifice is an honor reserved to God alone, because it is understood to be an act of adoration, such as can be offered to no creature.
From the beginning of man’s existence, a sacrifices have been offered to God. The children of Adam and Eve, Abel and Cain, offered sacrifice to God. Abel offered sheep; Cain, fruits of the earth.
Because they did not have a knowledge of the true God, the ancient Greeks and Egyptians offered human sacrifices. The Caananites used to offer human victims to their idol Moloch, heating the brazen statue of the god red-hot, and casting the victims into its arms. Even today some pagan peoples offer human sacrifices. Thus we see how perversion enters when the true God is not known.