On the surface, the answer is straight-forward: the people had not cleansed themselves by getting rid of the idols and/or jewelry of foreign gods.
Shortly after the incident at the Jordan, Joshua tells the people:
Now therefore fear the LORD and serve him in sincerity and in faithfulness. Put away the gods that your fathers served beyond the River and in Egypt, and serve the LORD.
(Joshua 24:15 ESV)
And the people said to Joshua, “No, but we will serve the LORD.” Then Joshua said to the people, “You are witnesses against yourselves that you have chosen the LORD, to serve him.” And they said, “We are witnesses.” He said, “Then put away the foreign gods that are among you, and incline your heart to the LORD, the God of Israel.” (Joshua 24:21-23 ESV)
The word "cleansed" in Joshua 22:17 is טָהֵר first used in Genesis describing a similar situation:
And Jacob saith unto his household, and unto all who [are] with him, `Turn aside the gods of the stranger which [are] in your midst, and cleanse yourselves, and change your garments
(Genesis 35:2 YLT)
Of Jacob's instructions the Pulpit Commentary says:
Put away the strange gods - literally, the gods of the stranger, including most likely the teraphim of Laban, which Rachel still retained, and other objects of idolatrous worship, either brought by Jacob's servants from Mesopotamia, or adopted in Canaan, or perhaps possessed by the captives - that are among you, and be clean, - literally, cleanse yourselves. [Genesis 35:2]
Jacob's family needed to cleanse themselves by getting rid of their objects which served as idols:
And they give unto Jacob all the gods of the stranger that [are] in their hand, and the rings that [are] in their ears, and Jacob hideth them under the oak which [is] by Shechem;
(Genesis 35:4 YLT)
By ridding themselves of the idols and certain jewelry representing the gods of the stranger, they were cleansed. In Joshua, some of the people, like Jacob's household, had objects in their possession from Peor. The people knew they had not cleansed themselves:
Have we not had enough of the sin at Peor from which even yet we have not cleansed ourselves… (Joshua 22:17 ESV)
Unlike Jacob’s family, the people had not disposed of their idolatrous objects and as a result, they knew they were not cleansed. Shortly thereafter Joshua tells them to put aware the foreign gods among you; presumably they do and Joshua renews the covenant (Joshua 24:14-26).
The difficulty with this scenario is in the conquest of Jericho where Achan takes items and hides them in his tent. This causes the LORD to say:
Israel has sinned; they have transgressed my covenant that I commanded them; they have taken some of the devoted things; they have stolen and lied and put them among their own belongings. Therefore the people of Israel cannot stand before their enemies. They turn their backs before their enemies, because they have become devoted for destruction. I will be with you no more, unless you destroy the devoted things from among you. Get up! Consecrate the people and say, ‘Consecrate yourselves for tomorrow; for thus says the LORD, God of Israel, “There are devoted things in your midst, O Israel. You cannot stand before your enemies until you take away the devoted things from among you.” (Joshua 7:11-13 ESV)
The only items which are removed are those found in Achan’s tent which had been taken from Jericho (not Peor). This implies there were no other items among the people.
There are several ways to reconcile the people having objects from Peor after Jericho:
- They had them when they entered the land and were considered their possessions, not devoted things which they had been instructed to destroy.
- They were disposed of but (some) went back (later) and recovered them.
- The cultic practices of Baal Peor were also followed in Canaan. When the people conquered those cities where they were not required to destroy everything, (some) people took new objects to replace the ones from Peor.
Regardless of whether the objects were original to event at Peor or replacements, their presence among the people recalled the events of Peor and the people knew they were not cleansed.
Atonement by Another
Atonement, כָּפַר [H3722-kaphar], means to cover. Literally to make atonement is to cover. At Baal Peor, Phinehas made atonement for the people of Israel by killing Zimri and Cozbi:
And the LORD said to Moses, “Phinehas the son of Eleazar, son of Aaron the priest, has turned back my wrath from the people of Israel, in that he was jealous with my jealousy among them, so that I did not consume the people of Israel in my jealousy. Therefore say, ‘Behold, I give to him my covenant of peace, and it shall be to him and to his descendants after him the covenant of a perpetual priesthood, because he was jealous for his God and made atonement for the people of Israel.’” (Numbers 25:10-13 ESV)
While there is no mention of cleansing in this event, this would come when the annual Day of Atonement ritual was completed:1
For on this day shall atonement be made for you to cleanse you. You shall be clean before the LORD from all your sins. (Leviticus 16:30 ESV)
The Day of Atonement calls for four animals: one bull, two goats, and one ram. The bull is a sin offering for the High Priest and for his house. The goats are for the people. The ram is for a burnt offering. One goat is killed to make atonement for the Holy Place and for the Tent of Meeting. Then blood of the goat and bull is used to make atonement for the altar before the LORD. Then the second goat is presented live. The High Priest places both hands on the head of the live goat and by confessing all of the transgression and sins of the people, puts them on the head of the goat. Then the goat is led away into the wilderness. When the ceremony is completed, the people’s sins are both covered and carried away and they are cleansed.
In comparing the cleansing which results from the actions of the High Priest with that called for by Jacob, there are notable differences. In one the High Priest acts on behalf of the people; in the other the people act themselves. In terms of sin and idols, in one the sins are carried off by the live goat; in the other, the idols are removed by the people. In other words, on the Day of Atonement the sins would be carried off leaving the idols in their place.
Similarly at Baal Peor, Phinehas made atonement for Israel by killing Zimri and Cozbi. But what became of the idols? There is no mention of Phinehas taking them away or of the people getting rid of them. Given the events described in Joshua, we must assume some of the people kept them.
The events in Joshua underscore a difference between atonement and being cleansed. The annual Atonement will make atonement, but if a single person has decided to be joined to Baal of Peor and keep their idols, that person is not cleansed and the presence of even a single person’s idols impacts everyone (as Achan did at Jericho).
In the commentary on Joshua Carol Meyers says about verse 22:17:
Recalling the sin of Peor…marks the seriousness of their action by comparing it to a particularly grievous sin, where according to the notion of corporate responsibility, the sins of a few can bring punishment to the whole.
At Baal Peor Phinehas made atonement for Israel and the plague was stopped because of his actions. He was rewarded with a covenant of peace and a covenant of perpetual priesthood. Nevertheless, year later the foreign gods of Peor remained among the people causing them to recognize they had not cleansed themselves.
1. There is no record of any Day of Atonement ceremony being carried out. The assumption is they were done according to the law.
2. Carol Meyers, The Jewish Study Bible, Oxford University Press, 2004, p. 502