Be strong when tempted to compromise
But the Israelites were unfaithful in regard to the devoted things; Achan son of Karmi, the son of Zimri, the son of Zerah, of the tribe of Judah, took some of them. So the Lord’s anger burned against Israel. Joshua 7:1 (NIV)
The bad choices of others will negatively affect you
6 Then Joshua tore his clothes and fell facedown to the ground before the ark of the Lord, remaining there till evening. The elders of Israel did the same, and sprinkled dust on their heads. Joshua 7:6 (NIV)
Whining is not living by strong and courageous faith
10 The Lord said to Joshua, “Stand up! What are you doing down on your face? 11 Israel has sinned; they have violated my covenant, which I commanded them to keep. They have taken some of the devoted things; they have stolen, they have lied, they have put them with their own possessions. 12 That is why the Israelites cannot stand against their enemies; they turn their backs and run because they have been made liable to destruction. I will not be with you anymore unless you destroy whatever among you is devoted to destruction. Joshua 7:10-12 (NIV)
Deal with sin in a way that honors God and honors others