Cage

The cage in the UPDV is a figure for confinement under judgment. It is named explicitly once, in Jeremiah, where the deceit of the wicked is compared to a cage full of trapped birds; and a parallel image stands at the fall of Babylon in Revelation, where the city itself becomes a holding-place for every unclean bird.

Houses Full of Deceit

Jeremiah's indictment compares the houses of the wicked to a bird-cage. The cage is full because the birds are trapped, and so are the deceits inside the houses: "As a cage is full of birds, so their houses are full of deceit: therefore they have become great, and waxed rich" (Jer 5:27). The figure ties wealth and greatness to confinement — what is held captive is also what is hoarded — and the cage marks the wicked house as a place of accumulated trickery.

Fallen Babylon as a Hold of Unclean Birds

In the cry over fallen Babylon the same image returns, recast for a city. Babylon is no longer a place where birds happen to be kept; the city itself has become the holding place: "And he cried with a mighty voice, saying, Fallen, fallen is Babylon the great, and has become a dwelling place of demons, and a hold of every unclean spirit, and a hold of every unclean bird, and a hold of every unclean and hateful beast" (Rev 18:2). The vocabulary shifts from "cage" to "hold," but the function is the same — a place where unclean birds are confined — and the city, like Jeremiah's deceit-filled houses, is named for what is trapped inside it.