Eschatology is the doctrine of the Last Things. It looks unto the future, and on the basis of the teaching of Scripture, sets out what will happen in the future. Some people allow their imagination to lead them into fantastical speculation. But theology should always be sober and restrained, and based upon what God has clearly revealed. In trying to interpret prophecy, we must exercise a measure of caution, as it is notoriously difficult to interpret. When Christ came the first time, he took almost everyone by surprise. Although the Jews had the wonderful and detailed prophecies of the Old Testament, and they had a clear idea in their own minds what would happen, it didn’t turn out as they expected. As one writer put it, when Christ came the first time, they all got it wrong. So it will be when Christ returns the second time. Even the best works of theology would be found to be somewhat inaccurate.
Let us look first then at the origin of death. Death is not natural, in the sense that it was not there from the beginning. When God first created the world, it was full of life, and there was no death anywhere. Adam was created in the image of God for fellowship with God. God entered into a covenant with him, promising him life on condition of perfect obedience, but threatening death on disobedience. If he obeyed God, he would live forever. But there was in the middle of the Garden of Eden the tree of knowledge of good and evil.