This letter, in all seriousness, is probably one of two things that existed in this world that I would readily trade a kidney for if given the chance. Beyond the content, which I still foam at the mouth thinking about, the timing is what gets to me with this one, because let's remember two things about this letter.
There's a very good chance that this letter contains Laurens' proper response to the Hamilton's June 30th letter, the one where he tells John about his engagement: The earliest response that we have from Laurens where we can reasonably assume he has knowledge of Hamilton's engagement is the infamous 'one-line hat commission' letter. I put it in quotations since I was rightfully corrected by @john-laurens when I made a post about it awhile back. They had brought to my attention that it was not a one-line letter and actually contains a snippet extra that founders doesn't have included on their website for some reason. Transcript copy-pasted below was provided by @john-laurens here (also a very big thank you to them for being the backbone of this community :))
โMrย Mitchel had put the execution of your commissions in such a brain, that he left me nothing more to do than to transport my head to Labors, and give some directions about your feather_ ย the whole will be committed to the care of Colonel Gimat_ย I will mount a beaver and plumage in the same stile as soon as I have a prospect of joining the Corps_ Your letter tho dated the 19thย did not reach me till yesterday_ as it came by the post and I am not in the habit of inquiring there for Letters_ ย General Cadwallader is just arrived in town, and I believe means shortly to pay you a visit at Head Quarters.ย What possesses Greene [for] the General Officers?_
My Love to the Family_
Adieu_
John Laurens.
30thย July 1780โ
Biggest thing that sticks out to me here is the lacking mention of Eliza and the length. It really says something about Laurens when he only acknowledges the July 19th letter, and not yknow- the other very important and very much older letter he received nearly a month ago. Like even if the July 19th letter was really all that important that it needed to be responded to first, it's not like he really says anything about it anyways, just puts a petty little acknowledgment that, "Yeah I got your letter FROM THE 19TH." Also I'm like 99% sure that send off of "My Love to the Family" is nothing special but the 1% chismosa in me loves thinking it's either 1) another pointed jab at the fact Laurens did in fact receive the June 30th letter and knows about Hamiltons newly acquired family or 2) Laurens referring to the military family but choosing that send off to spite Hamilton in pretending to be ignorant of the other family it could be referring too.
This is why I believe the September 8th letter definitely has more of a proper response to Hamilton's engagement. It's the next response after that very short July 30th letter and Hamilton's response is crazy telling. Like you said the reassurance, the 'impatience to have me married' and the cure bit? Oh boy. I could talk about it for days but I still want to say one other this about the timing of this letter.
2. This is the point in their correspondence where Laurens gets dry: Now, I'll preface this by saying that there's a pretty good chance that there are other Laurens letters we don't know of. I don't want to make the assumption that the lack of evidence for correspondence means that they weren't interacting, but I will say that this is the last response we know from Laurens for a longggg time. It goes September 8th 1780 letter right to his last letter of July 1782 (sob) Granted not all that time was with them apart, with the need to send letters, but there's a really big lull on Laurens side of things after this letter. Again makes me think that September letter was either 1) very petty 2) very emotional and vulnerable or 3) all of the above.
In conclusion, if the September 8th letter ever gets released to the public, know that I found a genie lamp and used my first wish very wisely.