“Bel.” Another name for Marduk, who was the chief god of Babylon. The name “Bel” is equivalent to the Canaanite “Baal;” both names mean “lord.” Isaiah 45 concerned the Persians and the Jew’s rebellion against God. Isaiah 46 opens with the gods of Babylon being defeated and disgraced.
It seems that Isaiah prophesied between c740-680 BC., and this should put in perspective the fact that he spoke of events that were over a hundred years after his life (which is why the scholars who do not believe in God think Isaiah was written much later than it was). Babylon conquered Judah and burned the Temple in Jerusalem in 586 BC, and the Persians did not conquer Babylon until 539 BC, which means that this prophecy in Isaiah 46:1 was likely fulfilled more than 150 years after it was spoken.
“bows down…stoops low.” The gods of Babylon bow before the Persian conquers.
“Their idols.” The idols of the Babylonians.