In Joshua 7, the Lord revealed Achan’s guilt in two ways. First, He spoke directly to Joshua at some length both to explain the reason for Israel’s defeat and to describe a process for identifying the one who had disobeyed by taking the “devoted” items (vv. 10–15). Second, the Lord singled Achan out in a kind of trial by elimination that involved the casting of lots (vv. 16–18). Joshua 7 describes how people come forward by tribe, clan, family, and then individually. Once identified, the guilty party would be punished (vv. 14–15).
The text does not explicitly state the exact means used to narrow the field of suspects except to say that the Lord would do the sorting (v. 14). This indictment made by divine revelation would then be confirmed by physical evidence after the guilty party was shown to have the forbidden items in their possession.
The sorting described in verses 10–15 suggests a binary method, where the answer to the question of guilt was either a yes or a no. It seems likely that this answer was obtained using the Urim and Thummim, objects placed in the high priest’s breastplate. According to Exodus 28:30, they were “a means of making decisions for the Israelites.” In 1 Samuel 14:42, the word “taken,” which repeatedly appears in Joshua 7, is used in a similar case that explicitly involved the use of the Urim and Thummim. Scripture does not describe their appearance except to indicate that they were small enough to be cast. They may have been small gems or stones, similar to dice.
This lengthy procedure was not carried out so God could learn who had taken the forbidden plunder. Rather, the process was intended to draw attention to the gravity of what had happened. The Lord already knew that Achan had committed the crime. The involvement of the entire congregation in his exposure underscored that Achan was not just guilty as an individual but had also brought guilt on the entire community by violating the covenant.