The promise in (Genesis 13:16) has a strange choice of image. God does not tell Abram his children will be like stars or like sand. Those images come later. Here the promise is as the dust of the earth.
Targum Pseudo-Jonathan renders the logic explicit: as it is impossible for a man to number the dust of the earth, so also it shall be impossible to number thy sons. The uncountability is the point.
Why dust? The Sages asked this question for centuries. Dust is trampled. Dust is humble. Dust is what Adam was formed from and what all flesh will return to (Genesis 3:19). To promise Abram's descendants as dust is to promise him a people who will be, in some sense, underfoot — small, scattered, mistaken for nothing, yet impossible to erase. You can trample dust. You cannot count it.
The Targumist preserves the comparison without softening its paradox. The founding promise of the Jewish people is not a promise of power. It is a promise of persistence. Dust survives storms by being too dispersed to sweep away completely. There is always more.
Later, in (Genesis 15:5) and (Genesis 22:17), the same promise will be reissued with different metaphors — the stars of heaven, the sand of the sea. Abram will be told his descendants are above and below, earth and sky. But the first image is dust. Before glory, humility. Before the stars, the ground.
It is a promise a wandering man can take with him. You do not need a palace to carry dust.