Atoning Sacrifice
Propitiation, taking a personal object, speaks of the appeasement of an offended party—specifically the Christian God—from wrath or anger.
that by which God is rendered propitious, i.e., by which it becomes consistent with his character and government to pardon and bless the sinner. The propitiation does not procure his love or make him loving; it only renders it consistent for him to exercise his love towards sinners.
Propitiation properly signifies the removal of wrath by the offering of a gift. In the OT it is expressed by the verb kipper (*ATONEMENT). In the NT the hilaskomai word group is the important one. In modern times the whole idea of propitiation has been strongly criticized as savouring of unworthy ideas of God. Many suggest that the term ‘propitiation’ should be abandoned in favour of *EXPIATION, and this is done, for example, in RSV.
Expiation speaks of the process by which sins are nullified or covered.
In the Bible both expiation and propitiation are part of God’s atoning work. Christ’s sacrifice both propitiates (turns away) the wrath of God and expiates (covers) human sin.