God's finished work, Glorification.
Glorification is God's final removal of sin from the life of those who have excepted the precious gift of eternal life. This comes in the eternal state (Romans 8:18, 2Corinthians 4:17). When looking at glorification, as Christians we should focus on Christ, for He is our blessed hope (Romans 5:2). Consider final glorification as reaching the highest point of sanctification. Until Christ returns we are burdened with sin, for our final glorification we have to wait on the return of our Savior Jesus Christ, (Titus 2:13, 1 Tim. 6:14, 1 Corn. 13:12). Each day that we wait on His return we should work hard by the Holy Spirit to put to death what is sinful and worldly in us (Romans 8:13). Only through prayer, the study of God's Word and direction of the Holy Spirit can we do this.
When and how will this happen? 1 Corinthians 15:51-53 says " Behold, I tell you a mystery: We shall not all sleep, but we shall all be changed in a moment, in the twinkling of an eye, at the last trumpet. For the trumpet will sound, and the dead will be raised incorruptible, and we shall be changed. For this corruptible must put on incorruption, and this mortal must put on immortality." So at the last trumpet, when Jesus comes for the saved (saints) an instant transformation will take place, at this time our sinful, decaying bodies will put on a body that is perfect and without sin ( 2 Corn. 3:18). To be glorified is another way of saying the believer will be "conformed" to the character of Christ which is God’s ultimate purpose for the Christian. No longer will the Christian "fall short of the glory of God" (Romans 3:23).
Jesus prayed in John 17, to sanctify us (make us holy) in the truth of His Word, This is necessary if we want to be with Jesus in eternal fellowship. Verse 24 says, “Father, I desire that they also, whom you have given me, may be with me where I am, to see my glory that you have given me because you loved me before the foundation of the world." If the glorification of the saints follows the pattern revealed in Scripture, it must entail our sharing in the glory (the holiness) of God. We will be perfectly conformed to the image of our Lord Jesus and be like Him free from sin and its consequences (1 John 3:2, Phill. 3:20-21).
Philippians 1:6. “For I am confident of this very thing, that He who began a good work in you will perfect it until the day of Christ Jesus.” So when the devil tries to make you question and doubt your being a "chosen vessel" of God's, just remember God is still working on you, working towards the final part of our salvation. God is in the process of perfecting us for that final day when Jesus returns for us,(His bride).
References: Mathew Henry Commentaries; The Holy Bible; Baker's Evangelical Dictionary