I will go before thee - To prepare the way for conquest, a proof that it is by the providence of God that the proud conquerors of the earth are enabled to triumph. The idea is, I will take away everything that would retard or oppose your victorious march.

And make the crooked paths straight - (See the note at Isaiah 40:4). The Chaldee renders this, 'My word shall go before thee, and I will prostrate the walls.' Lowth renders it, 'Make the mountains plain.' Noyes, 'Make the high places plain.' The Septuagint renders it, Ὄρη ὁμαλιῶ Orē homaliō - 'Level mountains.' Vulgate, Gloriosos terroe humiliabo - 'The high places of the earth I will bring down.' The word הדוּרים hădûrı̂ym is from הדר hâdar, to be large, ample, swollen, tumid; and probably means the swollen tumid places, that is, the hills or elevated places; and the idea is, that God would make them level, or would remove all obstructions out of his way.

I will break in pieces the gates of brass - Ancient cities were surrounded by walls, and secured by strong gates, which were not unfrequently made of brass. To Babylon there were one hundred gates, twenty-five on each side of the city, which, with their posts, were made of brass. 'In the circumference of the walls,' says Herodotus (i. 179), 'at different distances, were a hundred massy gates of brass, whose hinges and frames were of the same metal.' It was to this, doubtless, that the passage before us refers.

The bars of iron - With which the gates of the city were fastened. 'One method of securing the gates of fortified places among the ancients, was to cover them with thick plates of iron - a custom which is still used in the East, and seems to be of great antiquity. We learn from Pitts, that Algiers has five gates, and some of these have two, some three other gates within them, and some of them plated all over with iron. Pococke, speaking of a bridge near Antioch, called the iron bridge, says, that there are two towers belonging to it, the gates of which are covered with iron plates. Some of these gates are plated over with brass; such are the enormous gates of the principal mosque at Damascus, formerly the church of John the Baptist' (Paxton). The general idea in these passages is, that Cyrus would owe his success to divine interposition; and that that interposition would be so striking that it would be manifest that he owed his success to the favor of heaven. This was so clear in the history of Cyrus, that it is recognized by himself, and was also recognized even by the pagan who witnessed the success of his arms. Thus Cyrus says Ezra 1:2, 'Jehovah, God of heaven, hath given me all the kingdoms of the earth.' Thus Herodotus (i. 124) records the fact that Harpagus said in a letter to Cyrus, 'Son of Cambyses, heaven evidently favors you, or you could never have thus risen superior to fortune.' So Herodotus (i. 205) says that Cyrus regarded himself as endowed with powers more than human:, 'When he considered the special circumstances of his birth, he believed himself more than human. He reflected also on the prosperity of his arms, and that wherever he had extended his excursions, he had been followed by success and victory.'

The crooked places "The mountains" - For הדורים hodurim, crooked places, a word not easily accounted for in this place, the Septuagint read הררים hararim, τα ορη, the mountains. Two MSS. have הדרים hadarim, without the ו vau, which is hardly distinguishable from the reading of the Septuagint. The Divine protection that attended Cyrus, and rendered his expedition against Babylon easy and prosperous is finely expressed by God's going before him, and making the mountains level. The image is highly poetical: -

At vos, qua veniet, tumidi subsidite montes,

Et faciles curvis vallibus este viae.

Ovid, Amor. 2:16.

"Let the lofty mountains fall down,

and make level paths in the crooked valleys."

The gates of brass "The valves of brass" - Abydenus, apud, Euseb. Praep. Evang. 9:41, says, that the wall of Babylon had brazen gates. And Herodotus, i, 179. more particularly: "In the wall all round there are a hundred gates, all of brass; and so in like manner are the sides and the lintels." The gates likewise within the city, opening to the river from the several streets, were of brass; as were those also of the temple of Belus. - Herod. i., 180, 181.

I will go before thee, and make the crooked places straight,.... Or, "level the hilly places" (c); as pioneers do. The sense is, that he would remove all impediments and obstructions out of his way, and cause him to surmount all difficulties:

I will break in pieces the gates of brass, and cut in sunder the bars of iron; with which the brasen gates were barred: in the wall that surrounded Babylon there were a hundred gates, all made of solid brass, twenty five on each side of the square; which, no doubt, are here referred to; which could not hinder the entrance of Cyrus into the city, and the taking of it; though they were not then destroyed by him, but by Darius afterwards (d) these gates of brass are mentioned by Abydenus (e), as made by Nebuchadnezzar, and as continuing till the empire of the Macedonians.

(c) The Septuagint render the word by mountains; Gussetius by eminences, high places, such as stood in the way of passage into countries. The Vulgate Latin interprets it of glorious persons; and Abendana says it is right to understand it in this way; and applies it to Zerubbabel, and those that went up with him to Jerusalem, with the leave of Cyrus, who were good men, and honourable in their works, whom the Lord directed in their way right, and prospered them in the building of the temple, (d) Herodot. l. 1. c. 179. l. 3. c. 159. (e) Apud Euseb. Praepar. Evangel. l. 9. c. 41. p. 457.

I will go before thee, and make the {d} crooked places straight: I will break in pieces the gates of brass, and cut asunder the bars of iron:

(d) I will take away all impediments and hindrances.

45:2 Go - To remove all obstructions, to destroy all them that oppose thee, and carry thee through the greatest difficulties.

2. crooked . straight-(Isa 40:4), rather, "maketh mountains plain" [Lowth], that is, clear out of thy way all opposing persons and things. The Keri reads as in Isa 45:13, "make straight" (Margin).

gates of brass-(Ps 107:16). Herodotus (1.179) says, Babylon had a hundred massive gates, twenty-five on each of the four sides of the city, all, as well as their posts, of brass.

bars of iron-with which the gates were fastened.

45:1-4 Cyrus is called God's anointed; he was designed and qualified for his great service by the counsel of God. The gates of Babylon which led to the river, were left open the night that Cyrus marched his army into the empty channel. The Lord went before him, giving entrance to the cities he besieged. He gave him also treasures, which had been hidden in secret places. The true God was to Cyrus an unknown God; yet God foreknew him; he called him by his name. The exact fulfilment of this must have shown Cyrus that Jehovah was the only true God, and that it was for the sake of Israel that he was prospered. In all the changes of states and kingdoms, God works out the good of his church.