Let's take the case of the one passage in Romans translated with "propitiation" in the AV:
For all have sinned, and come short of the glory of God, being justified freely by his grace through the redemption that is in Christ Jesus, whom God hath set forth [to be] a propitiation through faith in his blood, to declare his righteousness for the remission of sins that are past ... (Romans 3:23-25)Another widely-used translation, the NIV, has that "propitiation" part as:
God presented him as a sacrifice of atonement, through faith in his bloodThere is also a footnote in the NIV with an alternate reading of:
the one who would turn aside his wrath, taking away sin.It's an interesting footnote, once you consider that the word "wrath" doesn't actually appear anywhere in the received text of that passage; neither does "turning aside wrath". That's a theological theory being read into the text based on assumptions about what "propitiation" is. The footnote may be trying to bring light to an obscure word in the text, but did they bring light to it, or further obscure it?
So if there are three places that the New Testament uses the word "propitiation", why look at that one passage in particular? Because it uses a different word than the other two in the original Greek. The passage in Romans uses a Greek word that is only used twice in the New Testament: there, and in Hebrews 9:5:
And over it, the cherubim of glory overshadowing the mercyseat (AV)Or in another translation:
Above the ark were the cherubim of the Glory, overshadowing the atonement cover. (NIV)That's quite a difference in translation: a propitiation, a sacrifice of atonement, one who would turn aside wrath taking away sin ... or the mercy seat of the Ark of the Covenant.
So what does that word typically mean? Although the New Testament only uses the word twice, we do have more than just those two uses for reference. The Hebrews had translated the Old Testament into Greek. We still have the text of the Septuagint, or the LXX, translation. And the Greek word that Paul used in Romans 3 is the normal word for the "mercy seat" or "atonement cover" of the Ark of the Covenant. You can check that by reading the Yom Kippur section of Leviticus in Greek, where the Greek word in question (hilasterion) is the word used for the mercy seat, or the cover of the Ark of the Covenant. In the Jewish usage of that day, that was the word in use for that specific place and object.
So Paul uses a word that is about Yom Kippur, the Day of Atonement. He links Christ to the Ark of the Covenant, to the one time a year that the high priest could enter the Holy of Holies and the presence of God. He links Christ to the one place on earth where someone could encounter the direct presence of God in the full glory of holiness. And specifically he links Christ to the "mercy seat" or "atonement cover".
And yet the Day of Atonement -- to read the ancient statutes of the Torah -- was focused on repentance and purification. And again, to read the New Testament letter to the Hebrews, the idea of the mercy seat is cleansing and purification. "Appeasing wrath" wasn't the purpose of the Day of Atonement, and it wasn't the idea in mind when they talked about the mercy seat. So it's really doubtful that Paul had appeasing wrath in mind when he used that word. With the Day of Atonement passages in mind, it seems more likely that he was alluding to the cleansing and purification that were the goal during the one time a year when the high priest approached the mercy seat.
For on that day shall the priest make an atonement for you, to cleanse you, that you may be clean from all your sins before the LORD. (Leviticus 16:30)