Really one of the better definitions of Spirit can be found in the 1859 American Tract Dictionary
SPIRIT
A word employed in various senses in Scripture.
1. For THE HOLY, HOLINESS SPIRIT, the third person of the Holy Trinity, who inspired the prophets, animates good men, pours his unction into our hearts, imparts to us life and comfort; and in whose name we are baptized and blessed, as well as in that of the Father and the Son. When the adjective Holy is applied to the term Spirit, we should always understand it as here explained; but there are many places whether it must be taken in this sense, although the term Holy is omitted. See HOLY, HOLINESS SPIRIT.
2. BREATH, respiration; or the principle of animal life, common to men and animal: this God has given, and this he recalls when he takes away life, Ec 3:21. See SOUL.
3. The RATIONAL SOUL which animates us, and preserves its being after the death of the body. That spiritual, reasoning, and choosing substance, which is capable of eternal happiness. See SOUL.
The "spirits in prison," 1Pe 3:19, it is generally thought, are the souls of antediluvian sinners now reserved unto the judgment-day, but unto whom the Spirit preached by the agency of Noah, etc., 2Pe 2:5, when they were in the flesh. Thus Christ "preached" to the Ephesians, whom he never visited in person, Eph 2:17.
4. An ANGEL, good or bad; a soul separate from the body, Mr 14:26. It is said, Ac 23:8, that the Sadducees denied the existence of angels and spirits. Christ, appearing to his disciples, said to them, Lu 24:39, "Handle me, and see; for a spirit hath not flesh and bones, as ye see me have."
5. The DISPOSITION of the mind or intellect. Thus we read of a spirit of jealously, a spirit of fornication, a spirit of prayer, a spirit of infirmity, a spirit of wisdom and understanding, a spirit of fear of the Lord, Ho 4:12 Zec 12:10 Lu 13:11 Isa 11:2.
6. The RENEWED NATURE of true believers, which is produced by the Holy Spirit, and conforms the soul to his likeness. Spirit is thus the opposite of flesh, Joh 3:6. This spirit is virally united with, an in some passages can hardly be distinguished from the "Spirit of Christ," which animates true Christians, the children of God, and distinguishes them from the children of darkness, who are animated by the spirit of the world, Ro 8:1-16. This indwelling Spirit is the gift of grace, of adoption-the Holy Spirit poured into our hearts-which emboldens us to call God "Abba, my Father." Those who are influenced by this Spirit "have crucified the flesh, with its affections and lusts," Ga 5:16-25.
"Distinguishing or discerning of spirits" consisted in discerning whether a man were really inspired by the Spirit of God, or was a false prophet, an impostor, who only followed the impulse of his own spirit or of Satan. Paul speaks, 1Co 12:10 of the discerning of spirits as being among the miraculous gifts granted by God to the faithful at the first settlement of Christianity.
To "quench the Spirit," 1Th 5:19, is a metaphorical expression easily understood. The Spirit may be quenched by forcing, as it were, that divine Agent to withdraw from us, by irregularity of life, frivolity, avarice, negligence, or other sins contrary to charity, truth, peace, and his other gifts and qualifications.
We "grieve" the Spirit of God by withstanding his holy inspirations, the impulses of his grace; or by living in a lukewarm and incautious manner; by despising his gifts, or neglecting them; by abusing his favors, either out of vanity, curiosity, or indifference. In a contrary sense, 2Ti 1:6, we "stir up" the Spirit of God which is in us, by the practice of virtue, by compliance with his inspirations, by fervor in his service, by renewing our gratitude, and by diligently serving Christ and doing the works of the Spirit.
(American Tract Society Bible Dictionary)
Luke 24
38He said to them, "Why are you troubled? Why do doubts arise in your hearts? 39See my hands and my feet, that it is truly me. Touch me and see, for a spirit doesnt have flesh and bones, as you see that I have." 40When he had said this, he showed them his hands and his feet. 41While they still didnt believe for joy, and wondered, he said to them, "Do you have anything here to eat?"
42They gave him a piece of a broiled fish and some honeycomb. 43He took them, and ate in front of them. 44He said to them, "This is what I told you, while I was still with you, that all things which are written in the law of Moses, the prophets, and the psalms, concerning me must be fulfilled."---World English Bible
Jamieson, Fausset, and Brown Commentary
39-43. Behold, &c.lovingly offering them both ocular and tangible demonstration of the reality of His resurrection.
a spirit hath notan important statement regarding "spirits."
flesh and bonesHe says not "flesh and blood"; for the blood is the life of the animal and corruptible body (Ge 9:4), which "cannot inherit the kingdom of God" (1Co 15:50); but "flesh and bones," implying the identity, but with diversity of laws, of the resurrection body. (See on Joh20:24).
The our resurrected body will be recognizable as us, but it will also be glorified in ways we don't understand now. We won't have blood, but we will have flesh and bone, as the JFB commentary pointed out, and these bodies will be able to go from one place to another instantly. These bodies will be indestructible. This is why the fate of the unbeliever is so terrible, he will suffer in hell for eternity because for one thing he will have an indestructible body.
John 20
11I saw a great white throne, and him who sat on it, from whose face the earth and the heaven fled away. There was found no place for them. 12I saw the dead, the great and the small, standing before the throne, and they opened books. Another book was opened, which is the book of life. The dead were judged out of the things which were written in the books, according to their works. 13The sea gave up the dead who were in it. Death and Hades gave up the dead who were in them. They were judged, each one according to his works. 14Death and Hades were thrown into the lake of fire. This is the second death, the lake of fire. 15If anyone was not found written in the book of life, he was cast into the lake of fire.---World English Bible
Barnes Commentary
Revelation of John 20:15:
Verse 15 And whosoever. All persons, of all ranks, ages, and conditions. No word could be more comprehensive than this. The single condition here stated, as being that which would save any from being cast into the lake of fire, is, that they are "found written in the book of life." All besides these--princes, kings, nobles, philosophers, statesmen, conquerors; rich men and poor men; the bond and the free; the young and the aged; the gay, the vain, the proud, and the sober; the modest and the humble--will be doomed to the lake of fire. Unlike in all other things, they will be alike in the only thing on which their eternal destiny will depend--that they have not so lived that their names have become recorded in the book of life. As they will also be destitute of true religion, there will be a propriety that they shall share the same doom in the future world.
Written in the book of life. Rev 3:5.
Was cast into the lake of fire. Mt 25:41. That is, they will be doomed to a punishment which will be well represented by their lingering in a sea of fire for ever. This is the termination of the judgment; the winding up of the affairs of men. The vision of John here rests for a moment on the doom of the wicked, and then turns to a more full contemplation of the happy lot of the righteous as detailed in the two closing chapters of the book.
(d.)--Condition of things referred to in Rev 20:11-15.
(1.) There will be a general resurrection of the dead--of the righteous and the wicked. This is implied by the statement that the "dead, small and great," were seen to stand before God; that "the sea gave up the dead which were in it;" that "Death and Hades gave up their dead." All were there whose names were or were not written in the book of life.
(2.) There will be a solemn and impartial judgment. How long a time this will occupy is not said, and is not necessary to be known-- for time is of no consequence where there is an eternity of devotion; but it is said that they will all be judged "according to their works"--that is, strictly according to their character. They will receive no arbitrary doom; they will have no sentence which will not be just. See Mt 25:31-46.
(3.) This will be the final judgment. After this, the affairs of the race will be put on a different footing. This will be the end of the present arrangements; the end of the present dispensations; the end of human probation. The great question to be determined in regard to our, world will have been settled; what the plan of redemption was intended; to accomplish on the earth will have been accomplished; the agency of the Divine Spirit in converting sinners will have come to an end; and the means of grace, as such, will be employed no more. There is not here or elsewhere an intimation that beyond this period any of these things will exist, or that the work of redemption, as such, will extend into the world beyond the judgment. As there is no intimation that the condition of the righteous will be changed, so there is none that the condition of the wicked will be; as there is no hint that the righteous will ever be exposed to temptation, or to the danger of falling into sin, so there is none that the offers of salvation will ever again be made to the wicked. . . . Rev 22:11.