Isaiah 45:3

“And I will give thee treasures of darkness, and hidden riches of secret places, &c.] What had been laid up in private places, and had not seen the light for many years. The Jewish Rabbins sayf880, that Nebuchadnezzar having amassed together all the riches of the world, when he drew near his end, considered with himself to whom he should leave it; and being unwilling to leave it to Evilmerodach, he ordered ships of brass to be built, and filled them with it, and dug a place in Euphrates, and hid them in it, and turned the river upon them; and that day that Cyrus ordered the temple to be built, the Lord revealed them to him: the riches of Croesus king of Lydia, taken by Cyrus, are meant;…”

“treasures of darkness--that is, hidden in subterranean places; a common Oriental practice. Sorcerers pretended to be able to show where such treasures were to be found; in opposition to their pretensions, God says, He will really give hidden treasures to Cyrus (Jer 50:37; Jer 51:13). PLINY (Natural History,, 33:3) says that Cyrus obtained from the conquest of Asia thirty-four thousand pounds weight of gold, besides golden vases, and five hundred thousand talents of silver, and the goblet of Semiramis, weighing fifteen talents. that thou mayest know--namely, not merely that He was "the God of Israel," but that He was Jehovah, the true God. Ezr 1:1-2 shows that the correspondence of the event…”

“And I will give thee the treasures of darkness - The treasures which kings have amassed, and which they have laid up in dark and secure places. The word ‘darkness,’ here, means that which was hidden, unknown, secret (compare Job 12:22). The treasures of the kings of the East were usually hidden in some obscure and strong place, and were not to be touched except in cases of pressing necessity. Alexander found vast quantities of treasure thus hidden among the Persians; and it was by taking such treasures that the rapacity of the soldiers who followed a conqueror was satisfied, and in fact by a division of the spoils thus taken that they were paid. There can be no doubt that large quantities of…”

“The treasures - Such as have been long kept in dark and secret places. Isaiah 45:4”

“45:3 so you may know: Cyrus’s victories provided factual proof that the Lord has the power to fulfill his plans, whereas idols and false gods do not (see 41:21-29).”

“I will give: Jer 27:5-7, Jer 50:37, Jer 51:53; Eze 29:19, Eze 29:20 that thou: Isa 41:23; Ezr 1:2 which call: Isa 43:1, Isa 48:15, Isa 49:1; Exo 33:12, Exo 33:17 Isaiah 45:4”