[1 of 4] Swedenborg (1688-1772, Sweden): primary subject "Immortality" (search under Afterlife/Afterlife, Heaven, Hell)": source "True Christian Religion": detail "Section 621"
Man, because he is capable of being conjoined with God by love and faith, lives to eternity: everyone has this capacity and that it is this which causes the soul's immortality, you may understand clearly, if you will but think a little more deeply than common on the subject.

[2 of 4] Swedenborg (1688-1772, Sweden): primary subject "Immortality" (search under Afterlife/Afterlife, Heaven, Hell)": source "Divine Providence": detail "Section 324[3] - 324[4]"
In order that a man may live forever, what is mortal with him is taken away. This mortal of his is his material body, which is taken away by its death. His immortal, which is his mind, is thus laid bare and he becomes a spirit in human form; his mind is this spirit. Ancient sages and wise men perceived that man's mind cannot die. They asked how the mind could die when it is capable of wisdom. Few today know the interior idea they had in this. It was the idea, slipping into their general perception from heaven, that God is wisdom itself, of which man partakes, and God is immortal or eternal.
 Since it has been granted me to speak with angels, I will say something from experience. I have spoken with those who lived many ages ago, with some who lived before the flood and some who lived after it, with some who lived at the time of the Lord and with one of his apostles, and with many who lived in the centuries since. They all seemed like men of middle age and said that they do not know what death can be unless it is condemnation. Further, all who have lived well, on coming into heaven, come into the state of early manhood in the world and continue in it to eternity, even those who had been old and decrepit in the world. Women, too, although they had become sunken and old, return into the bloom and beauty of their youth.

[3 of 4] Swedenborg (1688-1772, Sweden): primary subject "Immortality" (search under Afterlife/Afterlife, Heaven, Hell)": source "Of the Last Judgment and the Babylon which has been Destroyed": detail "Section 25"
The angels declare that with every man there is an inmost or supreme degree of life, or an inmost or supreme somewhat into which the Divine of the Lord primarily or proximately inflows, and from which He disposes all the remaining interiors belonging to the spiritual and natural man, which are successive in both according to gradations of order: this inmost or supreme they called the Lord's entrance into man, and His veriest dwelling place with him; and they said, that by this inmost or supreme, man is man, and is distinguished from brute animals which have it not; and that hence it is, that men, as regards the interiors which belong to their minds, rational and natural, unlike animals, may be elevated by the Lord to himself, may have faith in Him, may be affected by love to Him, may receive intelligence and wisdom, and speak from reason.
 When I asked them concerning those who deny the Divine, and the Divine Truths, by which the conjunction of the life of man with the Divine Himself is effected, and who live to eternity, notwithstanding their denial, they replied, that these also have the faculty of thinking and of willing, and therefore of believing and loving the things which are from the Divine, as well as those who acknowledge the Divine, and that by virtue of this faculty, they too live to eternity; and they added, that this faculty is from that inmost or supreme which is in every man and also possessed even by those who are in hell: hence it is, that every man lives to eternity, be he what he may. Because every man after death lives to eternity, no angel or spirit ever thinks of death; nay they are utterly ignorant of what it is to die. These things have been said in continuation that all the men who have ever been born, and have died, from the beginning of creation, are alive, some in heaven, and some in hell.

[4 of 4] Swedenborg (1688-1772, Sweden): primary subject "Soul" (search under Inner Life/Mind, Psyche, Soul, Spirit)": source "Conjugial Love": detail "Section 315"
You all are souls, of whose immortality you have heard, thought, said, and written so much; and because you are forms of love and wisdom from God, you can never die. The soul therefore is a human form, from which the smallest thing cannot be taken away, and to which the smallest thing cannot be added; and it is the inmost of all the forms of the whole body: and since the forms which are without receive from the inmost both essence and form, therefore you are souls, as you appear to yourselves and to us: in a word, the soul is the very man himself, because it is the inmost man; therefore its form is fully and perfectly the human form: nevertheless it is not life, but the proximate receptacle of life from God, and thereby the habitation of God.