Dates: c. 300 BC · Wikipedia
Summary: 1 Enoch 22 is the earliest detailed map of the structured intermediate state: the
dead are gathered into hollow chambers within a great mountain in the west, where the spirits are
separated into distinct divisions — the righteous beside a bright spring of water, sinners apart —
to await the day of judgement. It is the literary ancestor of the later Abraham's-bosom / place-of-torment
geography.
These hollow places have been created for this very purpose, that the spirits of the souls of the dead should assemble therein, yea that all the souls of the children of men should assemble here.
— The Book of Enoch (R.H. Charles tr.), 1 Enoch 22, ccel.org. In the vision Enoch is shown four "hollow places," deep and smooth, hewn in a great mountain in the west, where the spirits of all the dead are gathered after death.
And these places have been made to receive them till the day of their judgement and till their appointed period till the great judgement (comes) upon them.
— The Book of Enoch (R.H. Charles tr.), 1 Enoch 22, ccel.org. The intermediate state is explicitly provisional — a holding place "till the day of their judgement," not the final reward or punishment.
These three have been made that the spirits of the dead might be separated.
— The Book of Enoch (R.H. Charles tr.), 1 Enoch 22, ccel.org. The chambers are not undifferentiated: the dead are sorted by their moral standing, an early version of the two-destinies structure later read into Luke 16.
And such a division has been made (for) the spirits of the righteous, in which there is the bright spring of water.
— The Book of Enoch (R.H. Charles tr.), 1 Enoch 22, ccel.org. The righteous have a place of light and refreshment (the "bright spring of water"), while the sinners are held in a separate division apart from them — a foreshadowing of the comfort/torment contrast and the fixed gulf between them.