Isaiah 11:1-4

Each of the qualities of the mind is named to encourage us that this One, Jesus Christ, will hand down judgments of the highest quality. "Spirit" is the general word used to indicate those internal, immaterial, and unseen qualities of mind that energize and activate. We can see, both from God's Word and also from our own experiences, that they can be good or evil, edifying or destructive, clean or foul, generous or miserly, selfless or selfish, cheerful or depressive, positive or negative, etc. However, spirit always affects: It moves, activates, generates, impels, and creates in the direction of its force.

Why are cheerleaders used at football and basketball games? Is it not to generate a spirit? One cannot see the spirit that is energized. It is invisible, unseen. This illustration is no different in principle from what the Bible means by its use of "spirit."

John W. Ritenbaugh
The Holy Spirit and the Trinity (Part Two)

Revelation 12:7-9

Compare the language here with Daniel 10:5-21—spirit beings fighting and being cast down, even as humans fight. Only when humans fight, the loser is cast down in defeat and death. With the angelic beings, they are cast down in defeat, but there is no death.

How, then, is essence cast down? Arguments that posit spirit to be essentially insubstantial begin to become ridiculous. How does one cast down smoke, if we can think of essence in terms of smoke? Did Michael and his angels find big fans and blow the demon essence toward the earth? No, these verses give every indication that these spirit beings have substance. They are spirit, but they are substantial, tangible (that is, "capable of being perceived especially by the sense of touch"; synonyms are "palpable," "substantially real," "material").

Gabriel touched Daniel, and he was aware of feeling a hand touch him on the shoulder. Another time a hand touched him on the lips, and he was able to speak. The hand had substance.

John W. Ritenbaugh
Image and Likeness of God (Part Three)