“Thus said the Lord to His anointed (meshicho), to Cyrus, ‘He whose right hand I have strengthened, to lay nations flat before him, and [before whom] I shall open the [girded] loins of kings, to open doorways before him, and [for whom] gateways shall not be closed.'”
Rashi (ad loc):
“‘to His anointed (meshicho)’ – Any title of greatness is called, ‘anointing’… but our Sages said, to the King Messiah (Mashiach) the Holy One Blessed is He said: ‘I am complaining to you about Cyrus,’ as is recorded in Tractate Megilah (12A).”
Rav Nachman bar Rav Chisda expounded: What is the meaning of the verse: “Thus said the Lord to His anointed (‘meshicho’ — alt. ‘His Messiah’), to Cyrus, ‘He whose right hand I have strengthened'”? Was Cyrus the Messiah? Rather, the Holy One Blessed is He said to the Messiah, “I am complaining to you about Cyrus. I said he should build My House, and gather in My exiles, yet he said (Ezra 1:3): ‘Who among you from all His people… shall go up?'”
Ben Yehoyada (ad loc):
Why does the Holy One Blessed is He bring Cyrus’ judgment before the Messiah more than any of the kings of the nations of the world? …It appears to me, with Heaven’s help, that we have found in Haggai 2:9 that it is written regarding the Second Temple: “The glory of this final temple shall be greater than the first, says the Lord.” Therefore, there are those who wonder, saying, G-d forbid, ‘There is no hope for a Third Temple! Since this [Second] Temple is called ‘final,’ conclude therefore that there is none subsequent!’ The answer is that in truth it was the final [Temple] that would be built by flesh and blood, for none after would be built by flesh and blood. But the Third Temple for which we anticipate shall be the work of Heaven, upon which it was prophesied in the Song of the Sea: “The Sanctuary of the Lord, Your hands have established it.”
Some answer that indeed it was fitting that this Second Temple would be the final one, that it would not be destroyed and would remained standing, if Cyrus would have done what he was commanded by G-d, that he himself would ascend to build the Temple and also gather in all the exiles, for all the kingdoms were under his power, and he had the ability to bring up all of Israel, those near and far. Then that Temple would have been the final on that would never be destroyed, for the Holy One Blessed is He would have granted it afterward everlasting existence since its construction would have occurred via Cyrus in the agency of the Everpresent One Blessed is He. It would therefore have been considered as though it was made by Heaven. However, because Cyrus did not fulfill the Blessed Lord’s command regarding this Temple, his agency was nullified, for if an agent deviates from the agency of the sender, his agency is nullified. It was therefore considered as though [Cyrus] himself acted independently and [the Temple] was not considered as having been built by the Blessed Lord. Therefore, the promise that this [Temple] would be “final,” as the Blessed Lord had promised that it would be final, that it would not be destroyed and no other would need to be built in its place, was also nullified, and [the Temple] would be destroyed. Then the Blessed Lord will uphold His words with the Third Temple which will be built by Heaven, and that one will remain standing.
With this [understanding], the statement [of the Talmud] is well understood, for it is possible that the Messiah, when he heard the prophecy regarding the verse (in Haggai) that called the Second Temple “final,” and saw that it was destroyed subsequently, would be pained, for he would think that sin had caused [the nullification of the prophecy] and that hope of a Third Temple was lost, G-d forbid. Therefore, the Holy One Blessed is He tells him, “I am complaining to you about Cyrus, etc.,” for He thereby demonstrated to [the Messiah] that Cyrus had deviated from his instructed agency, and therefore the promise that [the Second Temple] would be final is void, and this Temple would not be the final one since its construction would not be considered the act of the Blessed Lord via His agency. Therefore, the matter still remains that He will fulfill His promise to rebuild the Temple with the Third Temple which will then stand forever. At that time, all the promises of Heaven will be fulfilled, including the greatness of the King Messiah. The intent, therefore, of the Blessed Lord with these words that He said to the Messiah was that he should know and understand that the promise that He, the Blessed Lord, would rebuild the Holy Temple had not yet been fulfilled, and that promise of finality that was said regarding the Second Temple was void, for now this [Second Temple] would not be final, rather the Third Temple, may it be build speedy in our days, amen, will be final, as we have said.