Albert Barnes Commentary Isaiah 46:2

"They stoop, they bow down together; they could not deliver the burden, but themselves are gone into captivity." — Isaiah 46:2 (ASV)

They stoop - Bel, and Nebo, and all the Babylonian gods .

They could not deliver the burden - The word ‘burden’ here probably means the load of metal, wood, and stone of which the idols were composed. The gods whom the Babylonians worshipped had not even power to protect the images made to represent them, which had now become a heavy burden to the animals and wagons carrying them away.

They could not rescue them from the hands of the conqueror; and how unable were they, therefore, to defend those who put their trust in them. The Vulgate renders this, ‘They could not deliver him that carried them.’ The Septuagint, ‘You are carrying them like a burden bound on the weary, faint, and hungry; who are all without strength, and unable to escape from battle; and as for them, they are carried away captives!’

But themselves - Margin, as Hebrew, ‘Their soul.’ The sense is that the gods thus worshipped, so far from being able to defend those who worshipped them, had themselves become captive, and were carried to a distant land.