“God was going to teach Israel a lesson. The lesson is this: Don’t disobey Me; if you do there will be severe consequence. The consequence was that Achan and his whole family, who evidently were implicated in the crime also, were all stoned to death. Now listen, why did he wantAchan to confess his sin? I’ll tell you why; because God would have looked like a cruel ogre if He had taken the life of this man and his family and nobody had known really why. When Achan confessed his sin he was saying, God, You as a holy, righteous God are free to punish me, free to chasten me with no impunity against Your righteous nature because I deserve it, you see?
Now maybe you’ve never thought of confession of sin that way but that’s exactly the heart of the matter. The reason God wants Achan to confess his sin is so that God is free to chasten him and not have anybody think that it was undeserved. God is a holy God, and God reacts against sin. He cannot tolerate sin. He cannot let sin go unpunished. If He could’ve He never would have had Jesus die. God must deal with sin. And God will look unjust, and God will look unfair in the eyes of people, if you and I do not admit that everything that God does to chasten us is deserved. And in verse 20 he said, “I have sinned against the Lord God of Israel.” He didn’t blame God, he didn’t blame the circumstances, he didn’t blame his influences; he accepted the responsibility. You have a similar situation at the crucifixion of Christ. The thief on the cross had dishonored God all his life. He had done exactly what he wanted to do and now he was hanging on a cross beside Jesus Christ. But in that very moment, the last moment of his life, hanging on a cross, for one time in his life he gave glory to God. You know what he said? He said to the other thief in Luke 23:41, “We indeed suffer justly.” In other words, he said, what are you complaining about fellow? You’re getting exactly what we deserve. In other words: you cannot dishonor God in this act, we deserve this, you cannot impugn God for this, we deserve it.”
GTY – MacArthur