Joshua 7

"'Get up! Command the people to purify themselves in preparation for tomorrow. For this is what the Lord, the God of Israel, says: Hidden among you, O Israel, are things set apart for the Lord. You will never defeat your enemies until you remove these things from among you.'" v.13
Things to be "set apart" refers to all the clothing, cattle and other plunder that God said to Israel should destroy when they conquered Jericho. It was not that they found a good use something that was going to be thrown out anyway. This was a serious offense because it was in direct defiance of an explicit command of God. Notice the results of Achan's sin:
1.) Many men died 7:5
2.) Israel's army melted in fear 7:5
3.) Joshua questioned God 7:7-9
4.) God threatened to withdraw his presence from the people 7:12
5.) Achan and his family had to be destroyed 7:24-26

When Israel eliminated the sin from their community, these were the results:
1.) God's encouragement 8:1
2.) God's presents in battle 8:1
3.) God's guidance and promise of victory 8:2
4.) God's permission to keep the plunder and livestock from the battle for themselves 8:2
Throughout Israel's history, blessings came when the people got rid of their sin. You will experience blessings when you turn from your sin and follow God's plan wholeheartedly.

Taken from the NLT Life Application Study Bible