Arcana by E Swedenborg http://smallcanonsearch.com/read.php?book=ac§ion=581
That by the “Nephilim” are signified those who through a persuasion of their own loftiness and preeminence made light of all things holy and true, appears from what precedes and what follows, namely, that they immersed the doctrinals of faith in their cupidities, signified by the “sons of God going in unto the daughters of man, and their bearing unto them.” Persuasion concerning self and its phantasies increases also according to the multitude of things that enter into it, till at length it becomes indelible; and when the doctrinals of faith are added thereto, then from principles of the strongest persuasion they make light of all things holy and true, and become “Nephilim.”
That race, which lived before the flood, is such that they so kill and suffocate all spirits by their most direful phantasies (which are poured forth by them as a poisonous and suffocating sphere) that the spirits are entirely deprived of the power of thinking, and feel half dead; and unless the Lord by His coming into the world had freed the world of spirits from that poisonous race, no one could have existed there, and consequently the human race, who are ruled by the Lord through spirits, would have perished.
They are therefore now kept in a hell under as it were a misty and dense rock, under the heel of the left foot, nor do they make the slightest attempt to rise out of it. Thus is the world of spirits free from this most dangerous crew, concerning which and its most poisonous sphere of persuasions, of the Lord’s Divine mercy hereafter. These are they who are called “Nephilim” and who make light of all things holy and true. Further mention is made of them in the Word, but their descendants were called “Anakim” and “Rephaim.” That they were called “Anakim” is evident
from Moses: There we saw the Nephilim, the sons of Anak, of the Nephilim, and we were in our own eyes as grasshoppers, and so we were in their eyes (Num. 13:33). and Rephaim: The Emim dwelt before in the land of Moab, a people great, and many, and tall, as the Anakim, who also were accounted Rephaim, as the Anakim, and the Moabites call them Emim (Deut. 2:10-11). The Nephilim are not mentioned anymore, but the Rephaim are, who are described by the prophets to be such as are above stated;
in Isaiah: Hell low down has been in commotion for thee, to meet thee in coming, it hath stirred up the Rephaim for thee (Isa. 14:9),
speaking of the hell which is the abode of such spirits. . . . Thy dead shall not live, the Rephaim shall not arise, because thou hast visited and destroyed them, and made all their memory to perish (Isa. 26:14), where also their hell is referred to, from which they shall no more rise again. In the same: Thy dead shall live, my corpse, they shall rise again; awake and sing, ye that dwell in the dust, for the dew of herbs is thy dew; but thou shalt cast out the land of the Rephaim (Isa. 26:19);
“the land of the Rephaim” is the hell above spoken of
In David: Wilt Thou show a wonder to the dead? Shall the Rephaim arise, shall they confess to Thee? (Ps. 88:10), speaking in like manner concerning the hell of the Rephaim, and that they cannot rise up and infest the sphere of the world of spirits with the very direful poison of their persuasions.