Jesus describes Satan as a murderer in addition to being a destroyer. A murderer destroys life. Jesus also calls him a liar. He does not dwell in the truth at all, deceiving all the time.
We are human beings, created in the image of God. We have tremendous capacity and potential, but we have used our powers just as the father of destruction, the father of lies, would have used them.
The Hebrew word ruach (translated as "spirit"), Greek pneuma (also translated as "spirit"), and the English "spirit" all mean basically the same thing. The same general implication underlies all of their applications: that of an often powerful, invisible, immaterial, motivating force. This unseen force inspires or encourages people to do something, good or bad. Its quality is not relevant at this point.
Thus, the Bible will use the Hebrew or Greek word for "spirit" for such invisible, motivating forces as "feelings" and "attitudes"—even "talents." E.W. Bullinger says in his Companion Bible that the Bible gives the word "spirit" eight different applications.
Human spirits are not always invisible—they can be observed on a face or felt by those nearby—but they work as a force to motivate behavior or reaction. For example, if we walk into a room where people are scowling or perhaps even angry, we are affected. We might wonder, "What got into them?" meaning "What inspired their attitude?" "Why the angry spirit?" If we stick around for even a short while—it will not take long—that negative spirit will begin motivating us to react.
Depending on the person with the negative attitude, the motivation to reaction could be swift! If that person happens to be our spouse, we can probably tell immediately that they are in a different spirit, and it will affect us right away. A spirit has flowed from one person to another.
This flow of spirit also works positively. If we are around someone who is really up and happy and congenial, an outgoing person, his or her spirit will affect us in a positive way. We enjoy being around such people because we feel better and their spirits motivate us to be like them.
These may be simple explanations, but that is how a spirit works. A spirit is invisible and immaterial, but it has powerful motivating effects. Because we have a spirit too, we can pick up on the spirit and attitude of other people—and of supernatural beings as well.
