(Jesus continues speaking to his disciples.)

## they have no more that they can do ##

"they cannot do anything else" or "they cannot cause any more harm" or "they cannot hurt you anymore"

## Fear the one who ##

This could also be translated as "Fear God who" or "Fear God, because."

## after he has killed ##

"after he kills you" or "after he kills someone"

## has authority to throw you into hell ##

This can be translated as "has authority to throw people into hell."