In "Doctrinal Discussion" William Sillings writes:
The captain of fears, according to John’s first epistle, is fear of punishment by God. “Herein is our love made perfect, that we may have boldness in the day of judgment: because as he is, so are we in this world. There is no fear in love; but perfect love casteth out fear: because fear hath torment. He that feareth is not made perfect in love” (4:17, 18). So, the wall plaque is correct, “The fear of God is the fear that drives out all others.”
It should not be assumed by this passage, however, that all fear is sinful or the result of not loving God. Some fears are lodged deep within the subconscious and need to be treated psychologically. They do not have spiritual roots. Nevertheless, even here the fear and love of God are often the keys to freedom from deep-seated fear which does not have moral overtones.
Source: Studies in the Psalms: Adult Teacher's Insights, page 26.