As the sun dipped low over the divided animals, a tardemah fell on Abraham — a deep, prophetic sleep. Targum Pseudo-Jonathan on Genesis 15:12 uses that sleep to show him the whole future at once, compressed into a single horrified doze.
Four kingdoms rose before him to enslave his children.
The Targum names them with a little Aramaic pun on each. Terror — that is Bavel, Babylon. Darkness — that is Madai, Media. Greatness — that is Javan, Greece. Decline — that is Pheras, Persia, which, the Targum adds, is to fall, and to have no uplifting, and from whence it is to be that the children of Israel will come up.
Every Jewish child who later lived under any of those empires could open this verse and find a calendar. Your oppressor is not eternal. He is item three of four on a list Abraham already saw in a dream. The Babylonians have a name. The Greeks have a name. Even the last of them has an expiration date.
The Maggid's comfort is structural. History is not an endless night; it is a sequence. Each kingdom gets a color — terror, darkness, greatness, decline — and each color fades into the next (Genesis 15:12). The sleep of the patriarch maps the exile of his children, and the map ends not with another empire but with Israel walking up out of it.