“forgetfulness.” The Hebrew word is neshiyah (#05388 נְשִׁיָּה), “forgetfulness” (the noun only occurs here, and is derived from the verbal root, “to forget,” so forgetfulness seems an appropriate translation). Although some modern lexicons and translations have “oblivion,” that seems more of a nuance than a literal translation.
Many commentators say that the “land of forgetfulness” is the land that is forgotten by God; that is, once a person dies God forgets him. But God does not forget us in the grave, even though it may seem that way. He remembers us and will bring us up from the grave at the Rapture or one of the resurrections. The “land of forgetfulness” is the grave, and the phrase refers to the fact that when people are dead they have no memory or thoughts (Ps. 6:5; 115:17; Eccles. 9:5-6, 10; Isa. 38:18-19).
People do not go to heaven, “Hell,” or Paradise when they die. They die and are dead in every sense of the word. They are in the earth awaiting the Rapture or one of the resurrections.
[For more on Sheol, see commentary on Rev. 20:13. For more on dead people being dead, lifeless in every way, see Appendix 4, “The Dead are Dead.” For more on what the “soul” is, and that it does not live on after a person dies, see Appendix 7, “Usages of ‘Soul.’”]