The people of Israel were living under the Mosaic covenant. The covenant that Achan broke when he coveted and took some of the devoted things was the covenant made at Sinai, of which Joshua’s words were an application (Joshua 6:18–19). The Mosaic covenant governed Israel’s communion with the Lord in the tabernacle worship (Leviticus), and its life in the land of Canaan (Deuteronomy). This covenant was an administration of the one covenant of grace made with Abraham, and it called for obedience (Leviticus 18:5). Obedience to the covenant was the condition for long life in the land of promise (e.g. Exodus 20:12; Deuteronomy 5:33).
11 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.