2 Thessalonians 2:13...But we are bound to give thanks alway to God for you, brethren beloved of the Lord, because God hath from the beginning chosen you to salvation through sanctification of the Spirit and belief of the truth
In the above passage Sanctification through the Spirit relates to the Churches "escape" from Divine Judgment as taught in the Thessalonian Letter. Divine Judgment is an event that will take place on Earth after the Rapture of the Church. Verses 1-12 of 2 Thessalonians... define in detail the "future Judgment" the Church will escape in the Rapture. "It is imperative to first read prior verses to understand the full context of this teaching."
Future Judgment is only for those who perish without Christ. God sends a strong delusion upon those who fell away and would not believe the love of the truth in this life. Future Judgment will allow the man of sin, the Anti-Christ, and the rise of Satan's Kingdom upon the Earth where there is no mercy or no Holy Spirit as we have today in this present Grace Age. In Future Judgment the Holy Spirit (the present hinderer of God's Wrath) will step out of the big picture. The Church will be "severed" or "cut away" from the unbelieving world and then the Anti-Christ will step in and take over for seven years as taught in Daniel's Prophecy. For further study review content in link below.
Biblical Facts about Daniel and the Holy Spirit, the Hinderer of God's Wrath
Sanctification through the Spirit in the above passage means to sever, to set aside, and/or to cut away. God severs and cuts away His body of believers in the Rapture of the Church. This cutting away is God's method of providing safety for His Church to escape future Wrath and Judgment. The Church, God's body of believer's consists of those who have obtained a moral holiness and a moral righteousness from belief in the truth about Christ in the present life. The members of this body obey the Gospel which in turn cleanses the heart from sin. This Sanctification through the Spirit takes place when God takes out this body of believers from an unbelieving world. Sanctification through the Spirit will be for those who accepted Christ and were obedient to His Holy presence in this life. Sanctification through the Spirit will be for those who did not fall away. Sanctification through the Spirit will be for those who are constantly, "Rapture ready with a clean heart". To meet with Christ in the Rapture...where the dead and Christ will rise and those who are alive will be caught up to meet with Him in the air.
Distinction between the Rapture of the Church and the return of Christ with all the Saints