If you go back to the first post, you can see why some believe you can be unsealed. If you believe you can have your name blotted out of the Book of Life, you can become unsealed. I have read through the Bible over and over again. I just finished it again about a week or two ago. It is not as plain as people want to say it is, regardless of which side you are on. I can find scripture to seemingly back up OSAS, perseverance of the Saints, predestination and election as taught by Calvin, and scripture that supports the idea you can lose your salvation after becoming a Christian. I have come to the conclusion we need to simply put our trust in Christ, and do the best we can to follow him.
How are you comparing the Church the Body of Christ with what is going on in the book of Revelation. Paul planly states that we are complete in Christ. The ones who are complete in Christ will be caught out before the things described in Matt 24 or 25 or Hebrews 6. Those things don't apply to the Church the Body of Christ.
4 There is one body, and one Spirit, even as ye are called in one hope of your calling;
5 One Lord, one faith, one baptism,
6 One God and Father of all, who is above all, and through all, and in you all.