Christian eschatology, a major branch of study within Christian theology, deals with "last things". Such eschatology – the word derives from two Greek roots meaning "last" (ἔσχατος) and "study" (-λογία) – involves the study of "end things", whether of the end of an individual life, of the end of the age, of the end of the world or of the nature of the Kingdom of God. Broadly speaking, Christian eschatology focuses on the ultimate destiny of individual souls and of the entire created order, based primarily upon biblical texts within the Old and New Testaments.
Christian eschatology looks to study and discuss matters such as death and the afterlife, Heaven and Hell, the second coming of Jesus, the resurrection of the dead, the rapture, the tribulation, millennialism, the end of the world, the Last Judgment, and the New Heaven and New Earth in the world to come.
Eschatology is important because of Christian hope and mission in life, or the lack of it, that derives from one's eschatology. If you believe the church is destined to fail in its efforts to win over the pagan nations, then you are not likely to make much of an effort to evangelize and disciple the nations. One's view of the future will have a dramatic influence in the way Christians make future plans regarding the fulfilment of the Great Commission. The following video clips discuss this important theme in more detail.