John Calvin Commentary Isaiah 45:2

"I will go before thee, and make the rough places smooth; I will break in pieces the doors of brass, and cut in sunder the bars of iron;" — Isaiah 45:2 (ASV)

1. And I will go before you. These two verses contain nothing new; but, in general, he shows that Cyrus will gain an easy and rapid victory, because he will have the Lord for the leader of his expedition. Accordingly he promises that all crooked paths will be made straight, because God will remove every obstruction.

Now, since money is the sinews of war, and Cyrus came from the scorched and poor mountains of Persia, Jehovah says that treasures which were formerly hidden and concealed will come into the hands of Cyrus, so that, laden with rich booty, he will have enough to cover any expenditure; for by the treasures of darkness he means those which lay concealed, and as it were buried in safe and deep places of defense.

It is abundantly clear from history that all these things happened; for by taking Croesus, king of Lydia, who was at that time the richest of all men, he obtained large sums of money. Nor would anyone have expected that he would gain victories so easily; and the reason for such great success is now added, because the Lord called and directed him, so that through him he might give an illustrious demonstration of his power; for he adds—

That you may know that I am Jehovah. True, Cyrus, as we formerly said, though he acknowledged that the God of Israel is the true God, and was filled with admiration, yet was not converted to him, and never embraced his pure worship according to the standard of the Law. This was therefore special knowledge, that is, so far as he assisted the Church, for whose deliverance he was appointed; and therefore it was necessary that he should be under the influence of this knowledge, so that he might carry out this work of God. Thus he does not speak of that knowledge by which we are enlightened, or about the Spirit of regeneration, but about special knowledge, such as men destitute of religion may possess.

Calling you by your name. From some commentators this mode of expression has received a trivial interpretation, that “before Cyrus was born, God called and described him by his name.” But we have seen in a former passage (Isaiah 43:1), that the Prophet, while he used the same form of expression, meant something different; for God is said to “call by name” those whom he has chosen, and whom he appoints to perform some particular work, so that they may be separated from the multitude. This word denotes a closer and more familiar connection. Thus a shepherd is said to “call his sheep by name” (John 10:3), because he knows them individually. This applies indeed, in the highest degree, to believers, whom God reckons as belonging to his flock, and to the number of the citizens of his Church. God did not bestow this favor on Cyrus; but because, by appointing him to be the leader of so excellent a deliverance, he engraved on him distinguished marks of his power, with good reason is the commendation of an excellent calling applied to him.

The God of Israel. This should be carefully observed; for superstitious men ascribe to their idols the victories which they have obtained, and, as Habakkuk (Habakkuk 1:16) says, They sacrifice every one to his god; and therefore they wander in their thoughts, and conceive in their hearts any deity that they fancy, while they should acknowledge that Jehovah is the only and true God. What is said of Cyrus should be much more applied to us, so that we may not fashion any knowledge of God according to our fancy, but may distinguish him from idols, so as to embrace him alone, and to know him in Christ alone, apart from whom nothing but an idol, or even a devil can be worshipped. In that respect, therefore, let us surpass Cyrus, to whom the knowledge of God was revealed, so that we may lay aside superstitions and all false worship, and may thus adore him in a holy and upright manner.