Nabu's fame in the ancient world was great enough that he appears, alongside his father Marduk, in a hostile mention within the Hebrew Bible. The book of Isaiah, in a passage widely read as directed against the gods of Babylon during the period of Judah's exile there, declares that Bel, a title of Marduk, bows down and Nebo, that is, Nabu, stoops, their images loaded onto beasts of burden and carried off as useless cargo unable to save themselves, let alone their worshippers, a deliberate mockery of two of the greatest gods of the empire that had conquered Jerusalem. That such a taunt made sense to its audience is itself a measure of how prominent Nabu had become by the sixth century BCE: by the Neo-Babylonian period he ranked second in the pantheon only to his father, and Nebuchadnezzar II, the king who destroyed Jerusalem's temple and whose own name honors Nabu directly, was among his most devoted royal patrons, funding lavish rebuilding at Borsippa's Ezida.
The biblical polemic, then, is not aimed at an obscure deity but at one of the two most powerful gods of the empire that had just conquered Judah, and its argument, that these gods are mere carved objects requiring transport rather than living powers, is a piece of genuine interreligious argument preserved from the ancient world, one side of a theological confrontation whose other side is recoverable only through the archaeology and inscriptions of Nabu's own cult.