Alie, the Malachi 3:17 reference is: 17 "They will be Mine," says the LORD of hosts, "on the day that I prepare My own possession, and I will spare them as a man spares his own son who serves him."
It means that God owns everything and when He recreates the world He intended humans to live in He will choose some of the dead to be reincarnated anew to live in that world.
Not very many people will get that chance as they prefer to worship other 'gods' ie 'alter egos' of Satan.