What is the theme in Assassins by Tim F. LaHaye?

The character's desire to do God's will is an apparent theme in this story, with Rayford's personal struggle the most prevalent. Rayford wants to be the one who kills Carpathia. Carpathia's death is prophesied and Rayford has no doubt that it's going to come to pass, and so he really wants to be the person to make that happen.