Isaiah 41:21

Produce your cause - This address is made to the same persons who are referred to in Isaiah 41:1 - the worshippers of idols; and the prophet here returns to the subject with reference to a further argument on the comparative power of Yahweh and idols. In the former part of the chapter, God had urged his claims to confidence from the fact that he had raised up Cyrus; that the idols were weak and feeble compared with him; and from the fact that it was his fixed purpose to defend his people, and to meet and refresh them when faint and weary. In the verses which follow Isaiah 41:21, he urges his claims to confidence from the fact that he alone was able to predict future events, and calls on the worshippers of idols to show their claims in the same manner. This is the ‘cause’ which is now to be tried.

Bring forth your strong reasons - Adduce the arguments which you deem to be of the greatest strength and power (compare the notes at Isaiah 41:1). The object is, to call on them to bring forward the most convincing demonstration on which they relied, of their power and their ability to save. The argument to which God appeals is, that he had foretold future events. He calls on them to show that they had given, or could give, equal demonstration of their divinity. Lowth regards this as a call on the idol-gods to come forth in person and show their strength. But the interpretation which supposes that it refers to their reasons, or arguments, accords better with the parallelism, and with the connection.