According to Revelation 20, on the surface there seem to be two different groups who are cast into the lake of fire: "death and hell", and "whosoever names are not written in the book of life". My question is this: Why does it mention one group of people that are cast into the lake of fire, and immediately afterward, mention another, when according to scriptures, all to be cast into the lake of fire belong to one group, that of those who have never believed. At the time of judgment, all the lost have already died, because of the return of Christ and of the millennium, so at that time, all the lost will have been in Hell. How do you explain this scripture?