Lamentations to Ezra
A prayer for restoration answered.
Restoration
This short prayer at the end of Lamentations asks Yahvah to bring everyone back to Jerusalem and make things like they were before the Babylonians destroyed Jerusalem. The decree at the very beginning of Ezra is just the answer. On the authority of Cyrus the Jews are encouraged to go back to Jerusalem and rebuild the temple. They are even given the temple articles, taken from the temple by the Babylonians, and they are resourced in other ways to carry out the decree.
The tight storyline between these books shows the cause and effect nature of prayer and events in the world. Someone prayed for restoration and when it was time the king was moved to pass a decree that would allow just that.
Authorship Connection
There's a strong tradition around the idea that Jeremiah wrote Lamentations, but this is not stated directly in the Bible and I generally stay away from using off-Bible sources for Bible issues. My experience is that the Bible tells us what we need to know and what we're not told is not important, but that it often tells more than we expect if we know how to use the systems in the Bible to unpack the Bible. (The systems described on this website are good examples of systems that unpack additional dimensions of scripture.)
In the case of finding the author of Lamentations, there's a backdoor built on the understanding that Ezra is read after Lamentations. When we read Ezra right after Lamentations we're told the author directly. Look at the first verse of Ezra again.
"That the word of Yahvah by the mouth of Jeremiah the prophet might be fulfilled" is a double entendre. Normally the statement is thought to refer to the 70 year prophecy in the book of Jeremiah. I agree with that understanding, but would argue there's a second meaning tied to the immediate, local, Lamentations-Ezra context.
In the immediate context the decree is a fulfillment of a prayer, not a prophecy. So who uttered the prayer? We're told the fulfillment was of something Jeremiah said. That makes Jeremiah the one who said the prayer and that makes him the author of Lamentations.
Reign
The subject of reign also connects these books. In Lamentations the author says "our crown has fallen." He's saying their sovereignty has ended. They no longer have their own king. They have come under the rule of a foreign nation. In contrast they state that Yahvah's throne endures from generation to generation, which means his reign does not end, but more specifically, he reigns over the reign of each and every king. The point this is making within Lamentations is that Yahvah took the crown from their head. They admit it was not without cause when they say "we have sinned."
In Ezra the same theme of Yahvah's reign over the reigns of kings is made wonderfully clear. Cyrus says that his authority to reign was given to him by Yahvah.