Now that we are less than a week away from Eternity Sunday, I want to highly recommend an excellent resource. Dr. Jeffrey Gibbs (exegetical professor at Concordia St. Louis) published a book based on his doctoral thesis several years ago. It is entitled Jerusalem and the Parousia. I read the pertinent sections of the book each time we approach the final three Sundays in the Church lectionary. Although he deals with the Gospel of Matthew, I have found that the material fits nicely with the other Synoptic Gospels (I fondly remember my theology class on the Synoptics all those years ago at university!).
I truly enjoy preaching on the final three Sundays of the lectionary. I am glad that the LSB lectionary got us back to the traditional practice of always using the readings for the final three Sundays in the lectionary. I had always done this since I was ordained. Those last three Sundays are so comforting and realign our thoughts as to how God will do things rather than the drivel we are served up by popular books, television specials, televangelists, and tabloid news regarding the return of Christ.
I do, however, think that the traditional One-year Lectionary preserves the themes of the last three Sundays in the Church year better than the Three-Year Lectionary. How I enjoy celebrating Eternity Sunday with Matthew's Wise and Foolish Virgins parable and the hymn "Wake, Awake, the Night is Flying".
All theology is Christology, and all Christology is eschatology (the study of the last day). Jesus inaugurated the last days with His incarnation and highlighted the last days with His death and resurrection. He is the firstfruits of the resurrection and the assurance that when He returns we will be raised up with a perfect and holy body. What an event to long for and rejoice in!