You do not need to fear arrows that fly during the day. Our fears which terrorize us during the night can just seem to be worrying thoughts in the daytime. But again the Lord says we have no reason to fear. They cannot even find you!
A refuge is what we need in the middle of a storm or in the middle of a battle. A fortress is the place where we seek protection, and from which we fight the enemy. Whatever our needs in life, whatever we are running from, or fighting against, the Lord's shelter is the place to run to or to fight from. For He is the security we need in every circumstance.
I have often found myself being disappointed by the number of Christians I know who are ill! Not seriously ill, (although there are many who are), but who suffer from colds and flu, and the sort of wintery sicknesses that most people have come to expect.