This section contains a situation that threatened the plan of God. Verses 12-20 contain an accusation against the 2.5 tribes that were featured in the beginning of Joshua. It was perceived that they had built an unauthorized altar. However, that was not the case (cf. vv. 21-29 for their explanation). Verse 31, thankfully, contain the resolution. Attempts to maintain holiness must be balanced with the need to maintain unity. The scenario does show us how devastating sin is in the assembly of Believers. God’s people took sin very seriously because they knew that God’s anger would lash out against “the whole congregation of Israel” (v. 18) if this perceived sin went unpunished. Emphasis on the altar and sacrifices points to our Savior’s death for sin and the creation of His unified Body.