Israel has cast off that which is good. The enemy will pursue him.
The reason for this destruction is not left out.  It was because Israel had "cast off" that which was good.  They had cast off the knowledge of the true God, forsaken all the blessed promises of the covenant, and taken up greedily the licentious and drunken ways of the pagan Canaanites, even wallowing in the sensuality of the immoral orgies of their shameful bull-gods.  How could God use such a nation any further?