The body returns to the dust from whence it came, but the souls are immortal from the time they begin to exist; they cannot just disappear and go out of existence. They will exist without body in Heaven or Hades until Christ comes to end the world and bring in the New Heavens and New Earth. The elect then will receive a glorious body like that of Jesus and enjoy endless fellowship with the God Triune, while the reprobates will receive physical bodies just to be tormented in the lake of fire.
The Intermediate State describes the time between death and the resurrection of the body, this includes a discussion of the immortality of the soul, Heaven and Hades.
The Immortality Of The Soul
While people are buried and their bodies return to the dust from whence they came, their souls do not cease to exist, they are immortal. While the body decomposes and returns to dust, the soul of man lives evermore. It is important to define the usage of the word “immortal” and “immortality” here. This immortality which the souls of men and angels possess is obviously not like the essential immortality of God. In 1 Timothy 6:16 we read that God “alone has immortality”. This speaks about God essentially and by nature having immortality. He ever was and ever will be immortal, i.e., undying. Albert Barnes noted on that passage that God has immortality “by his very nature, and it is in his case underived, and he cannot be deprived of it. It is one of the essential attributes of his being, that he will always exist, and that death cannot reach him”. But this word is often used in reference to men and angels, so what does it mean? It means that the souls of men and angels are undying from the moment that they come to exist. It means that the soul of man does not simply decompose or disappear after death, like the physical body does. Rather, the soul is unable to die, because God designed it to be so. There is no “must-ness” that the souls of man or of angels be immortal except that God had willed them to be so. It is not essential, as it is in the case of God, that our souls be immortal. Rather, this immortality is derived from God and is dependent upon His power. Louis Berkhof writes, ‘the word “immortality” designates, especially in eschatological language, that state of man in which he is impervious to death and cannot possibly become its prey.’ The word “immortal”, though it may be controversial to some, is used simply to indicate that the souls of men “neither die nor sleep”, while their bodies sure do until the resurrection.
While the Bible does not have a statement saying “the soul of man is immortal,” it very much, I believe, assumes and does not question it. For example, had the Fall not taken place, man would have lived forever in body and soul, but the Fall brought physical death to the body, yet it did not destroy the soul of man. The soul of man remained, but now in enmity with God, no longer walking in fellowship and peace with Him. Death is said to have come because of sin (Rom. 5:12; 6:23). Therefore, if sin had not come there would be no death. Notice that we're speaking here no...