The question, “Can a soul or spirit be destroyed?” is an important one. Some oppose literal destruction by resorting to the reasoning that people are spiritual beings, and “By definition, a spirit cannot die. A spirit is an immortal being” (Robertson 72).
You’ll notice that anyone who makes such an argument will fail to quote any Biblical passages to support this definition. That’s because there are none. Nor does a standard English dictionary support this definition. The Funk and Wagnall’s dictionary defines ‘spirit’ as “A supernatural and immaterial being.” A spirit is an immaterial being, that’s all. This certainly doesn’t mean an immaterial being is unable to die.
Answering the question, “Can a soul or spirit be destroyed?” is as simple as this: Whatever creature God gives life to he can bring death to. Whatever he creates he can also de-create. The human mind or disembodied soul did not always exist; it was created by God out of immaterial substances and given consciousness by God’s “breath of life.” And the simple fact is that whatever is created can be de-created, that is, destroyed. If God justly decides that a human being is worthy of death—soul and body—he certainly has the power to do it, after all, he’s the One who created human beings. Jesus Christ Himself declared that this is exactly what God will do to people on judgment day when they’re cast into the lake of fire (Matthew 10:28).
The exception would be creatures who willingly accept God’s gift of unconditional immortality, specifically the devil and his angels. God will one day grant unconditional immortality to people, but only those who have been redeemed through spiritual rebirth in Christ. Such people will have “the right to the tree of life” and live forever (see Revelation 22:14,19 and 2:7). As for unredeemed human beings, God refuses to grant such people this right because they’d have to exist forever in a miserable fallen state, like the fallen angels. Needless to say, unconditional immortality as such would be a curse. This is why, after Adam sinned and spiritually died, God said: “He must not be allowed to reach out his hand and take also from the tree of life and eat, and live forever” (Genesis 3:22). God therefore denied Adam access to the tree of life (verses 23-24). See Chapter Four for more details on this matter.
Human beings presently have yet to attain unconditional immortality and therefore are mercifully subject to literal death and destruction as justly deemed by the Almighty.