Shakespeare has advised us that:
Cowards die many times before their deaths;
The valiant never taste of death but once.
Of all the wonders that I yet have heard,
It seems to me most strange that men should fear;
Seeing that death, a necessary end,
Will come when it will come.
"Julius Caesar", Act 2 scene 2
This is a rather "prudential" and "unemotional" approach to fear, it seems to me. Quite rational. It makes me think of that song I like (or at least the title of that song): Why Worry?
To the extent that fear is debilitating; to the extent that Faulkner is right, and that we will prevail in this life only insofar as we can face our fears, and then forget them; to the extent that by our fears we import death to life before its time, and lose, therefore, the life we have..."
Fear not" is good advice, indeed, commanded or not.