If you are born once, you will die twice. If you are born twice, you will die once. By "born once," We mean the physical birth. By "born twice," we mean a physical birth as well as a spiritual birth in which you are born again, spiritually putting your faith in Christ.
Just as there are two births, the Bible teaches there are two deaths: one is physical, and the other is spiritual. Jesus warned that we are to fear the second death more than the first one.
Revelation 20:14 tells us, "Then Death and Hades were cast into the lake of fire. This is the second death." The second death is mentioned again in Revelation 21:8, which says, "But the cowardly, unbelieving, abominable, murderers, sexually immoral, sorcerers, idolaters, and all liars shall have their part in the lake which burns with fire and brimstone, which is the second death." The second death is Hell.
One commentator wrote, "The second death is the continuance of spiritual death in another and timeless existence." Another wrote, "Eternity to the godly is a day that has no sunset. Eternity to the wicked is a night that has no sunrise."
Jesus spoke of Hell in a very specific way. He warned of the fire of Hell (see Matthew 5:22). He warned about our bodies being thrown into Hell (see Matthew 5:29). And He spoke of the soul and the body being destroyed in Hell (see Matthew 10:28).
The Bible teaches that all Christians—defined as sinners who have been converted by putting their faith in Jesus Christ—will be in Heaven. And that offer of forgiveness is for everyone. Your eternal destination is really your choice. Not everyone will be saved in the end—only those who put their faith in Jesus Christ.