Psalm 91

He who dwells in the shelter of the Most High will remain secure and rest in the shadow of the Almighty (whose power no enemy can withstand).  I will say of the Lord, “He is my refuge and my fortress, My God, in whom I trust (with great confidence, and on whom I rely).”

When we keep close to God and follow His word, we remain under His shelter.  The protection of God is around us because we are concentrating on our relationship with God.  We can rely on God to help us cast down doubts and remind ourselves that He is our refuge and fortress.