Luke 12:5

But I will forewarn you whom ye shall fear,
I will be your monitor, and direct you to the proper object of fear and reverence, and whom you should be careful to displease and offend:

fear him, which after he hath killed;
your body, as the Persic version adds; hath taken away the life of it, by separating soul and body asunder, by sending one disease or another, or death in one shape or another:

hath power to cast into hell;
your soul, as the above version also adds; yea, to destroy both body and soul in hell, as in (See Gill on Matthew 10:28)

yea, I say unto you, fear him;
and none else, not with a servile, but with a filial fear.