“But...” The main theme of this chapter is the covetous sin of Achan, which affected all Israel. Israel was to be individually and corporately set apart, holy, to Yahweh. The one person’s sin affected the whole camp. The severity of the judgment upon Achan and his family may seem shocking to modern ears, but it must be remembered that the sin of Achan and his family (because they all knew about it) caused the death of 36 people! Most modern legal systems do not, in practice, acknowledge that the only thing as valuable as a life is another life, and that is the logic of God’s law. Achan’s sin involved a disobedience and covetousness which claimed a right to ownership of the spoils, and therefore the land, apart from God. But the land and what is on it belongs to Yahweh, and He gives it to His people, who are separate from the world. If Israel was to become like the Canaanites, they would, like the Canaanites, be destroyed.
“the children of Israel were unfaithful.” The family of Achan was unfaithful, but from God’s perspective, the nation as a whole was unfaithful. There is a community aspect to life, and in the Middle East people were not so much thought of as an individual as they were as part of a community. Often we see the king of Israel represent the whole nation.
“unfaithful, yes, unfaithful.” The figure of speech polyptoton for emphasis (cp. Gen. 2:16).
“the son of Zerah.” Judah and Tamar had more than one son. The Christ line came from Perez, but this is a line of Judah that did not lead to Christ (cp. Gen. 46:12; 1 Chron. 2:4).
“the anger of Yahweh burned.” The Hebrew is idiomatic: “the nose of Yahweh burned.” When we are angry our nose gets red and hot.