We are designed to live a victorious life (2Co 2:4-17; 2Co 3:4-6). Rahab and Achan are believers intended to enjoy victory. Rahab, though is the only one exalted in scripture (Mat 1:5); she lived a victorious life. The Israelites were highly favored. However, we are recipients of greater Grace and revelation than the children of Israel during Joshua's time. God's Justice never rests; He will bless or curse. Achan thought he could pick and chose what he could obey. Hebrew cherem means "dedicated to God", also can be translated "accursed". Achan took items dedicated to God that were provisions for the tabernacle and the poor. We're not our own; we're to be dedicated to God (1Co 6:19-20). Achan is the head of a large family in the tribe of Judah. He made himself the center of his life. Justice warns us again and again (Heb 10:32-39). After demonstrating faith, how shall we escape if we turn away from Him (Heb 12:25-29). "Our God is a consuming fire" (Heb 12:29); fire doesn't harm gold, silver, diamonds, but consumes dead wood.
Victorious life begins with personal purity; it's not a showy life like the Pharisees. Achan's family participated in his sin. At Ai, Joshua was told to take spoil for himself (Jos 8:1-2). Ingredients of a victorious life: 1) Victorious Christian recognizes his sinfulness; 2) pursuit of fellowship with God; 3) maintains his hunger for the Word of God (2Co 3:18); 4) life of prayer (Heb 4:16)