Time and Space

In our fallen state we are creatures of time and space, but Eternity does not need them.
Here in Plate 17 of Milton he has left Eternity for a redemptive purpose.

Milton Plate 15 [17] Erdman 109-10:

First Milton saw Albion upon the Rock of Ages,

Deadly pale outstretchd and snowy cold, storm coverd;

A Giant form of perfect beauty outstretchd on the rock

New York Public Library Milton

Copy C, Plate 38

In solemn death: the Sea of Time & Space thunderd aloud

Against the rock, which was inwrapped with the weeds of death
Hovering over the cold bosom, in its vortex Milton bent down

To the bosom of death, what was underneath soon seemd above.

A cloudy heaven mingled with stormy seas in loudest ruin;

But as a wintry globe descends precipitant thro' Beulah bursting,

With thunders loud and terrible: so Miltons shadow fell
Precipitant loud thundring into the Sea of Time & Space.

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Sea of Time and Space

Blake's Myth Again  has a detailed description of the image above.  It's taken from Homer's Cave of the Nymphs.
In Matthew 7:13-14 Jesus spoke of two gates, a wide one that leads to destruction and the narrow one that leads to life.