Judges 7, part 1: crouching soldier, lapping dog-man

Now that Gideon has successfully made war on the idolatry of Israel, he is ready to make war on Midian. Yet, outnumbered four to one, God tells him his army is too big. Holy war cannot be fought, except by men who believe, so two thirds of the army must be sent away. This remains true within the church. Yet still the people are too many, so God refines them a second time, until they are outnumbered 450 to one. But why does he use the lappy-dog test? Why does Gideon need an army of 300 dog-like misfits? And what is the significance for us in the church?