That five dollar theological term simply means “the study of the eschaton” (the last day). The Bible divides time into two great epochs: this present age and the age to come. We live in the now; we await the not yet. Scripture anticipates the end from the start. When Genesis 1:1 says, “In the beginning…” it is already preparing the way for what the Torah calls “the end of days” (see Deut. 4:30). When Jesus proclaimed that God’s Kingdom was at hand, he was announcing the in-breaking of the age to come, and Peter specifically spoke of the arrival of “the last days” on the day of Pentecost.
The intriguing characteristic of Biblical eschatology is that the age to come actually breaks in and infiltrates the present age now, before the end. Therefore, theologians speak of the “already” and the “not yet.” By grace through faith, believers are raised up with Christ into the new creation already even as they hope for its consummation when Christ returns and the dead are resurrected. We live simultaneously as citizens of two worlds, continually looking forward and moving toward a goal that not only defines our future but also transforms our present.
Eschatology is not just a teaching of the Bible, it is the very structure of reality, the context of creation and new creation, the enlivening power of the Christian’s life.
Today, here is a remarkable passage from Jürgen Moltmann that I encourage you to savor and keep in mind throughout this Advent season.
Eschatology was long called the ‘doctrine of the last things’ or the ‘doctrine of the end’. By these last things were meant events which will one day break upon man, history and the world at the end of time. They included the return of Christ in universal glory, the judgment of the world and the consummation of the kingdom, the general resurrection of the dead and the new creation of all things. These end events were to break into this world from somewhere beyond history, and to put an end to the history in which all things here live and move. But the relegating of these events to the ‘last day’ robbed them of their directive, uplifting and critical significance for all the days which are spent here, this side of the end, in history. Thus these teachings about the end led a peculiarly barren existence at the end of Christian dogmatics. They were like a loosely attached appendix that wandered off into obscure irrelevancies. They bore no relation to the doctrines of the cross and resurrection, the exaltation and sovereignty of Christ, and did not derive from these by any logical necessity. They were as far removed from them as All Souls’ Day sermons are from Easter. The more Christianity became an organization for discipleship under the auspices of the Roman state religion and persistently upheld the claims of that religion, the more eschatology and its mobilizing, revolutionizing, and critical effects upon history as it has now to be lived were left to fanatical sects and revolutionary groups. Owing to the fact that Christian faith banished from its life the future hope by which it is upheld, and relegated the future to a beyond, or to eternity, whereas the biblical testimonies which it handed on are yet full to the brim with future hope of a messianic kind for the world, — owing to this, hope emigrated as it were from the Church and turned in one distorted form or another against the Church.
In actual fact, however, eschatology means the doctrine of the Christian hope, which embraces both the object hoped for and also the hope inspired by it. From first to last, and not merely in the epilogue, Christianity is eschatology, is hope, forward looking and forward moving, and therefore also revolutionizing and transforming the present. The eschatological is not one element of Christianity, but it is the medium of Christian faith as such, the key in which everything in it is set, the glow that suffuses everything here in the dawn of an expected new day. For Christian faith lives from the raising of the crucified Christ, and strains after the promises of the universal future of Christ. Eschatology is the passionate suffering and passionate longing kindled by the Messiah. Hence eschatology cannot really be only a part of Christian doctrine. Rather, the eschatological outlook is characteristic of all Christian proclamation, of every Christian existence and of the whole Church. There is therefore only one real problem in Christian theology, which its own object forces upon it and which it in turn forces on mankind and on human thought: the problem of the future. For the element of otherness that encounters us in the hope of the Old and New Testaments — the thing we cannot already think out and picture for ourselves on the basis of the given world and of the experiences we already have of that world — is one that confronts us with a promise of something new and with the hope of a future given by God. The God spoken of here is no intra-worldly or extra-worldly God, but the ‘God of hope’ (Rom. 15.13), a God with ‘future as his essential nature’ (as E. Bloch puts it), as made known in Exodus and in Israelite prophecy, the God whom we therefore cannot really have in us or over us but always only before us, who encounters us in his promises for the future, and whom we therefore cannot ‘have’ either, but can only await in active hope. A proper theology would therefore have to be constructed in the light of its future goal. Eschatology should not be its end, but its beginning.