Luke 12:4-5
4 And I say unto you my friends, Be not afraid of them that kill the body, and after that have no more that they can do.
5 But I will forewarn you whom ye shall fear: Fear him, which after he hath killed hath power to cast into hell; yea, I say unto you, Fear him.
The Grace New Testament Commentary - Luke 12:4-5
12:4 The discourse then turned to those who felt threatened by pharisaic power and pressured to conform to their ways. Jesus communicated His compassionate stance by addressing His audience as "My friends," and assuring them they need not fear men.
12:5 Jesus then directs their fear in the proper direction. God the Father retains ultimate authority over life and over hell. This verse thus dispels the popular myth that the devil has charge of hell. The admonition has diverse applications to the listening audience. The disciples who had believed in Jesus need not fear hell (lit. Gehenna). They should lovingly respect the Father and stand in awe of Him (rather than of the Pharisees). On the other hand, any unbelievers in the crowd had reason to fear future condemnation.