After the Ark returned, the people spent 20 years lamenting the loss they had suffered before Samuel challenged them to put away their false gods. It was after this time of national repentance that their enemies decided to attack.
We, also, need to lament the state we have allowed our nation to fall into. We need to put away our idols of greed and pride and selfish pursuits and seek first the kingdom of God. We can be sure the enemy will attack, but our God will deliver us.