People have a body, a spirit and a soul. God can divide all 3.
The soulish part of man is more like the mind.
The spirit of a man is what is spiritual and alive to God.
The body is obviously, the physical you.
1 Corinthians 6
16 Or do you not know that he who is joined to a harlot is one body
with her? For “the two,” He says, “shall become one flesh.”
17 But he who is joined to the Lord is one spirit
with Him.
We are joined together to the Lord, one spirit with Him. But we are not one body or one mind with God are we.
What God saves is the spirit of a man.
1 Corinthians 5
3 For I indeed, as absent in body but present in spirit, have already judged (as though I were present) him who has so done this deed. 4 In the name of our Lord Jesus Christ, when you are gathered together, along with my spirit, with the power of our Lord Jesus Christ, 5 deliver such a one to Satan for the destruction of the flesh,
that his spirit may be saved in the day of the Lord [c]Jesus.
Such a person may well lose everything except salvation, see the DAY of Christ to come will test everyone's works by FIRE.
All their works may burn up. Since their spirit is joined to the Lord as one spirit with Him, that will be saved.
Getting a new spirit from God is an eternal work of God and He is living in that place, so then that spirit is saved, it is why our salvation is an eternal salvation.
1 Corinthians 3
9 For we are God’s fellow workers; you are God’s field,
you are God’s building. 10 According to the grace of God which was given to me, as a wise master builder I have laid the foundation, and another builds on it. But let each one take heed how he builds on it. 11 For no other foundation can anyone lay than that which is laid, which is Jesus Christ.
12 Now if anyone builds on this foundation
with gold, silver, precious stones, wood, hay, straw,
13 each one’s work will become clear; for the Day will declare it, because it will be revealed by fire; and the fire will test each one’s work, of what sort it is. 14 If anyone’s work which he has built on
it endures, he will receive a reward.
15 If anyone’s work is burned, he will suffer loss; but he himself will be saved, yet so as through fire.
16 Do you not know that you are the temple of God and
that the Spirit of God dwells in you?
17 If anyone [
b]defiles the temple of God, God will destroy him. For the temple of God is holy, which
temple you are.
The body is resurrected, and in that process glorified., changed, we get a new body, we do not keep the same body we have now.
The mind, well, you need to submit your mind to the will of God for you, which is your sanctification. Study scriptures, do the things that God says, do not conform your mind to the ways of this world, otherwise it may be stunned, wiped out on that day, you may lose a lot from what could have been rewards wise.
In essence the only thing that we certainly retain as we are now, if born of God, is our new spirit created in righteousness and holiness. The body and the mind are subject to rewards or the lack of them.
Not saying anyone will be unhappy in heaven. Heaven has levels of rewards and multiple levels. Christ compares it to being rulers over cities and siting on His right hand. Their remains a hierarchy in Heaven with God, an order.
Your mind has an obligation to God to be sanctified as is your new spirit created in righteousness and holiness.
v23 is the mind, which is under your control
v24 is the new man (new spirit)
Conform your mind to the new man that God created inside you.
And it will go well with you at the judgement Day
20 But you have not so learned Christ, 21 if indeed you have heard Him and have been taught by Him, as the truth is in Jesus: 22 that you put off, concerning your former conduct, the old man which grows corrupt according to the deceitful lusts, 23
and be renewed in the spirit of your mind, 24 and
that you put on the new man which was created according to God, in true righteousness and holiness.
More context
Ephesians 4
17 This I say, therefore, and testify in the Lord, that you should no longer walk as [
f]the rest of the Gentiles walk, in the futility of their mind, 18 having their understanding darkened, being alienated from the life of God, because of the ignorance that is in them, because of the blindness of their heart; 19 who, being past feeling, have given themselves over to lewdness, to work all uncleanness with greediness.
20 But you have not so learned Christ, 21 if indeed you have heard Him and have been taught by Him, as the truth is in Jesus: 22 that you put off, concerning your former conduct, the old man which grows corrupt according to the deceitful lusts, 23 and be renewed in the spirit of your mind, 24 and that you put on the new man which was created according to God, in true righteousness and holiness.
Do Not Grieve the Spirit
25 Therefore, putting away lying, “
Let each one
of you speak truth with his neighbor,” for we are members of one another. 26 “Be angry, and do not sin”: do not let the sun go down on your wrath, 27 nor give [
g]place to the devil. 28 Let him who stole steal no longer, but rather let him labor, working with
his hands what is good, that he may have something to give him who has need. 29 Let no corrupt word proceed out of your mouth, but what is good for necessary [
h]edification, that it may impart grace to the hearers. 30 And do not grieve the Holy Spirit of God, by whom you were sealed for the day of redemption. 31 Let all bitterness, wrath, anger, [
i]clamor, and evil speaking be put away from you, with all malice. 32 And be kind to one another, tenderhearted, forgiving one another, even as God in Christ forgave you.