In 1 Peter 3:4, Peter referred to the spirit as the “hidden person,” indicating that the spirit is a person. Paul, too, referred to the spirit as the “inner man,” indicating his belief that the human spirit is not just a concept or a force, but a person:
Therefore we do not lose heart, but though our outer man is decaying, yet our inner man is being renewed day by day (2 Cor. 4:16; emphasis added).
The “outer man” obviously describes the physical body, whereas the “inner man” defines the spirit. While the body grows older, the spirit never ages because it is eternal.
Notice again that Paul refers to both body and spirit as men. So when you imagine your spirit, don’t imagine a spiritual cloud. It is better to imagine a person with a form who looks like you. If your body is old, however, don’t think that your spirit looks old. Imagine how you looked in the prime of your life because your spirit has never grown older! It is renewed day by day.
Your spirit is the part of you that is born again (if you have believed in the Lord Jesus). Your spirit is joined with God’s Spirit (see 1 Cor. 6:17), and He is the one who guides you as you follow Jesus (see Rom. 10:14).
The Bible teachers that God is also a spirit (see John 4:24), and so are angels and demons. They all have forms and they all exist in the spiritual realm. The spiritual realm, however, cannot be perceived with our physical senses. Attempting to contact the spiritual world with our physical senses would be comparable to trying to feel radio signals with our hands. We cannot perceive with our physical senses that radio waves are traveling through a room, but that doesn’t prove there are no radio waves present. The only way to tune in to the radio frequencies is to turn on a radio.
This is also true of the spiritual realm. Just because the spiritual realm can’t be perceived with the physical senses does not disprove its existence. It does exist, and whether people realize it or not, they are part of the spiritual realm because they are spiritual beings. They are either spiritually related to Satan (if they have not repented) or spiritually related to God (if they are born again). Some spiritualists have learned how to relate to the spiritual world through their spirits, but they are contacting the realm of Satan’s domain—the kingdom of darkness.