Psalm 3:3, 5 "But you are a shield around me, O Lord; you bestow glory on me and lift up my head...I lie down and sleep; I wake again, because the Lord sustains me."
I was surprised to read in Elizabeth Marquardt's book that she had fears of someone breaking into her house. I've always had that fear, as long as I can remember, and it never made sense until I read her book. She asserts that many children of divorce fear for their safety because typically our fathers were absent, the fathers that we instinctively rely on to protect us from things that go bump in the night. Even as stepfathers and husbands come along later in our lives, that early experience leaves us feeling vulnerable and afraid at times.
David's sense of security and protection was in the Lord. He was fleeing from his son Absalom, probably sleeping in caves with a handful of men who had remained faithful to him. His shield was not his own proven fighting acumen, the swords and courage of the loyal men with him, and certainly not the high walls of a protected city or castle. David realized that his only real protection came from the Lord.
Every moment of every day (and night), the Lord is your shield--watching over you, protecting you, sheltering you. Nestled in the hollow of His hand, you can rest assured that He will sustain you and protect you until the day He calls you home to an eternity of peace and gladness.