The doctrine of salvation, of which the basis is found both in the OT and the NT. The Israelites were saved from slavery in Egypt; in Christian experience there is need for liberation from the slavery to sin and death. OT images and expectations were adopted and reinterpreted by Christians, including the sacrificial language of the OT. Paul (Rom. 3: 25) asserts that God put forward Christ as a sacrifice of atonement by his blood; this has sometimes been understood as meaning that God needed to be propitiated by the sacrificial blood of his Son. Such an interpretation, however, seems incompatible with justice—that someone innocent should be punished in place of a criminal. Others understand NT soteriology in terms of God's love and grace: God in Christ went to such lengths to manifest his love, and so win the response of repentance from human beings. The salvation promised by Christ is, as it were, a liberty to captives (Luke 4: 18), and some modern theologians would include in the captivity the enslaving forces of economics and conflict.