When someone is described as
God-fearing, it rarely means "
fear" in the common sense. Rather, it describes a sense of
respect or
awe for
God (or at least, for one's
perception of God).
When someone "puts the fear of God" into someone else, though, the common definition of "fear" usually is intended. More accurately, it's a fear of impending divine retribution. This obviously works better on believers than atheists.