SFC,
Paul said in 1 Cor. 5:5 "To deliver such an one unto Satan for the destruction of the flesh, that the spirit may be saved in the day of the Lord Jesus Christ."
This is speak of the Holy Spirit.
When we accepted Christ, the Holy Spirit comes in us and He is sealed in us - Eph. 1:13. Just like we are engaged with Christ, we are not yet marry to Christ till second coming of Revelation chapter 19. Revelation chapter 19 mentioned of 'Marriage of the Lamb'. Wife shall be make her ready and being dress in white robe or garment to marry Bride. Christ is our Bride, IF we continue to the end. In Hebrews 3:6 says, "But Christ as son over his own house; whose house are we, IF we HOLD FAST the confidence and the rejoicing of the hope firm unto the end."
If we do not hold fast the confidence and the hope till the end(at our death or Lord comes), then we shall not be God's household, and we would not be Christ's child(Rev. 21:7).
Back to 1 Cor. 5:5. It speaks of be remain in the Spirit, because are sealed with the spirit, till the day of redemption (Eph. 4:30). WE should not grieve the Holy Spirit, because He dwells in us, and being sealed. If we grieve Holy Spirit, then we would be no longer being sealed, and our soul shall not be delivery in the day of Christ, that means, if we sinning and turn away from the Lord, by the time, we die or Lord comes, we shall not be saved (Matt. 24:13), we shall be destruction(Matt. 7:13), that means both our body and soul shall be send into everlasting fire. So, we should fear of the Lord - Matt. 10:28.
Romans 11:19-23 telling us, we should fear at the Lord, because He have the power to cut us off, if we do not continue with our faith. Same as in John chapter 15 telling us, we might be cut off and cast away in the fire.
Yes, Christ can give our soul to Satan, if we turn away from the Lord. One thing that Satan cannot touch our soul, he have no power and authority. Only God have the authority. If we turn away from Him, He would loosed us out of his Hand, and allow Satan to take over us.
Bible commands us, we should look up at Christ daily, and hold our hope of eternal life, lest us away from it, we must steadfast and hold our hope till the end, or, if we do not endure it, then we would be destruction at the end- Matt. 7:13.
Entering the gate of eternal life of Matt. 7:14 is not easy life, our process of salvation life is hardship. We must be endure through it to the end, and we shall overcome them and be victory to receive eternal life. Obivous, there are many passages with conditionals in the Bible with "if's", "hold fast", "continue", "steadfast", etc.
If we fail them in our life, at the end, we shall not be saved (Matt. 10:22; Matt. 24:13), we would be end up in everlasting life.
In Christ
Rev. 22:20 -Amen!