Sacrifice is the fundamental act of religion, through which we acknowledge our dependence on God and express our desire for union with Him. This desire is symbolized by offering a gift to God, representing our intention to offer ourselves to Him. However, due to sin, sacrifice also takes on the character of expiation.
Through sacrifice, we not only affirm our dependence on God as our Creator, but also confess our sinfulness and our need for God's forgiveness. This is symbolized by the immolation of the gift, such as the shedding of the blood of an animal victim. When God accepts the sacrifice, it brings about reconciliation, and the acceptance is signified by receiving back the gift in communion, symbolizing God's blessing.
Thus, sacrifice is a deeply religious act where man, by offering himself through a victim, turns to God, who is his ultimate good (offering or oblation), and renounces sin, which is his evil (immolation). The divine acceptance of the sacrifice sanctifies the offering and establishes the sought-after heavenly alliance (communion).