Real power is not founded on military might, but rather on fear of the eternal, self-existent One, and hope in the solid rock of His love(vs. 18). We must depend upon God's redemption when the threat of physical domination or harm is imminent.
Perhaps He will direct us to resist in kind, or to stand firm in prayer and let Him demonstrate His power over the enemy, but we must be open to either possibility. Discerning His direction and standing in it tests our faith more than any other challenge.
But what should we do when we can't discern His will for our response to a dangerous situation? Saul sought out the witch of En-dor for help, calling on her to bring Samuel forth from Sheol for his prophetic direction(1Sa_28:7-25). When Samuel came up, however, he clarified for Saul exactly why the Lord had not directed him; because of his disobedience, the Lord had turned away from Saul. Otherwise God's direction would have been clear.
When we're facing a lose-lose situation and can't get God's direction, we must not seek advice from ungodly sources. By "ungodly sources" is meant any "wisdom" that is not from or is contrary to God's word. Saul sought out a godly man's direction, which would have been the right thing to do if Samuel did not happen to be dead.
There is no compensating for our failed walk with the Lord. We must fall on our faces to beg His forgiveness and His power to enable us to repent of our faithlessness. And we must continue in that prayerful attitude until He answers our entreaty. Then we must learn from our error and grow from our distress, or we are doomed to repeat the failure time and again.