My Speculation about the future

In the future, people would be able to rise people from the dead. As we know in the Bible that Jesus is the firstborn from the dead. Though Elisha did rose the son of the shunammite woman before the resurrection of Jesus Christ, the 'firstborn' concept still holds. The resurrections by Jesus will be resurrections to the eternal life, in a new body, new earth, free from sin.Therefore I think that when people discovered how to raise people from the dead, they do not have to already believed in Jesus, they might die again.
What Christians must do is to keep on telling the good news, the gospel to the world.