Revelation 2:11

The first death we must endure unless the Lord should suddenly come to His temple. For this let us abide in readiness, awaiting it without fear, since Jesus has transformed death from a dreary cavern into a passage leading to glory.

The thing to be feared is not the first but the second death, not the parting of the soul from the body but the final separation of the entire man from God. This is death indeed. This death kills all peace, joy, happiness, hope. When God is gone, all is gone. Such a death is far worse than ceasing to be: it is existence without the life which makes existence worth the having.