Commentators have argued about how Romans 3:25 how should be translated. Some translators use the work propitiation
Whom God set forth as a propitiation by His blood (NKJV).Others have used the word expiation.
Whom God put forward as an expiation by his blood (RSV).Some modern translations use the neutral but meaningless expression, “atoning sacrifice”.
God presented Christ as a sacrifice of atonement (NIV).The Greek word is “hilasterion”. In Hebrews 9:5, it is used to describe the cover of ark of the covenant in the Holy of Holies of the tabernacle. Our problem is that none of these words mean much to modern readers.
The word propitiate is directed towards a person. Someone is offended and they must be satisfied. Others do not like the word, because they thing it means that God is angry and hard to please.
Those who argue for propitiate are correct that Romans 3:25 describes Jesus as satisfying or appeasing “someone”, but they are wrong about who that person is. They assume that it is God the one who needs to be propitiated. That is wrong. God is gracious and great in love, mercy and patience, so he does not need to be propitiated.
Everyone who sins is a slave of the spiritual powers of evil. They demand the implementation of the curse of the law against everyone who sins, so we need to be ransomed from their power. They need to be propitiated, because they are operating according to the letter of the law and demanding retribution on all sinners.
Romans 3:25 says that Jesus has satisfied the powers of evil and redeemed us from their power. His death fulfilled the requirements of the law, cancelling out the demands of our accusers. It nullified the curse of the law that was against us.
If we trust in Jesus, we died with him and rose with him. That means our old life is dead. A prosecutor cannot bring charges against someone who is dead. The powers of evil have no rights over our lives.
They cannot object to that because they have already agreed that Adam’s sin gives them authority over all his descendants, ie everyone sinned in Adam. They have used that principle for all it is worth, so they cannot disagree with the parallel truth that all who believe in Jesus died with him and rose with him to a new life. They want us to share in Adam’s sin and loss of authority, so they cannot object to us sharing in what Jesus established as the head of the new covenant.