This is one of my favorite Lincoln letters.
He had just received a letter from his recently married friend Joshua F. Speed.
On this date in 1842, Lincoln penned an extraordinary reply.
In the first 200 words, Lincoln conveys how happy he is for his friend, but then he transitions to his own sad situation:
I am not going beyond the truth, when I tell you, that the short space it took me to read your last letter, gave me more pleasure, than the total sum of all I have enjoyed since that fatal first of Jany.'41.
For the next 100 words, Lincoln makes no effort to conceal his frustration. His troubled courtship with Mary Todd comes bubbling toward the surface. Speed and his new bride were happy, but Mary consumes Lincoln’s thoughts. He had made her unhappy. “That still kills my soul,” Lincoln writes. “I can not but reproach myself, for even wishing to be happy while she is otherwise.”
Lincoln suddenly stops himself from descending further into despair, but notice, it never completely fades away:
Dear Speed: Springfield, March 27th. 1842
Yours of the 10th. Inst. was received three or four days since. You know I am sincere, when I tell you, the pleasure it's contents gave me was and is inexpressible. As to your farm matter, I have no sympathy with you. I have no farm, nor ever expect to have; and, consequently, have not studied the subject enough to be much interested with it. I can only say that I am glad you are satisfied and pleased with it.
But on that other subject, to me of the most intense interest, whether in joy or sorrow, I never had the power to withhold my sympathy from you. It can not be told, how it now thrills me with joy, to hear you say you are ``far happier than you ever expected to be.'' That much I know is enough. I know you too well to suppose your expectations were not, at least sometimes, extravagant; and if the reality exceeds them all, I say, enough, dear Lord. I am not going beyond the truth, when I tell you, that the short space it took me to read your last letter, gave me more pleasure, than the total sum of all I have enjoyed since that fatal first of Jany.'41 . Since then, it seems to me, I should have been entirely happy, but for the never-absent idea, that there is one still unhappy whom I have contributed to make so. That still kills my soul. I can not but reproach myself, for even wishing to be happy while she is otherwise. She accompanied a large party on the Rail Road cars, to Jack-sonville last monday; and on her return, spoke, so that I heard of it, of having enjoyed the trip exceedingly. God be praised for that.
You know with what sleepless vigilance I have watched you, ever since the commencement of your affair; and altho' I am now almost confident it is useless, I can not forbear once more to say that I think it is even yet possible for your spirits to flag down and leave you miserable. If they should, dont fail to remember that they can not long remain so.
One thing I can tell you which I know you will be glad to hear; and that is, that I have seen Sarah,  and scrutinized her feelings as well as I could, and am fully convinced, she is far happier now, than she has been for the last fifteen months past.
You will see by the last Sangamo Journal that I made a Temperance speech on the 22. of Feb. which I claim that Fanny and you shall read as an act of charity to me; for I can not learn that any body else has read it, or is likely to. Fortunately, it is not very long and I shall deem it a sufficient compliance with my request, if one of you listens while the other reads it. As to your Lockridge matter, it is only necessary to say that there has been no court since you left, and that the next, commences to-morrow morning, during which I suppose we can not fail to get a judgement. 
I wish you would learn of Everett  what he will take, over and above a discharge for all trouble we have been at, to take his business out of our hands and give it to somebody else. It is impossible to collect money on that or any other claim here now; and altho' you know I am not a very petulant ma[n,] I declare I am almost out of patience with [Mr.] Everett's endless importunity. It seems like [he n]to only writes all the letters he can himself; b[ut] gets every body else in Louisville and vicinity to be constantly writing to us about his claim.
I have always [h]eard that Mr. Evere[tt is] a very clever fellow, and I am very [sorry] he can not be obliged; but it does seem to me he ought to know we are interested [to] collect his money, and therefore would do [it] if we could. I am neither joking nor in a [pet] when I say we would thank him to transfer h[is] business to some other, without any compensation for what we have done, provided he will see the court cost paid, for which we are security.
The sweet violet you enclosed, came safely to hand, but it was so dry, and mashed so fla[t,] that it crumbled to dust at the first attempt to handle it. The juice that mashed out of it, stained a [place] on the letter, which I mean to preserve and ch[erish] for the sake of her who procured it to be se[nt.] My renewed good wishes to her, in particula[r,] and generally to all such of your relatives as know me. As ever LINCOLN
 ALS, IHi
 The date on which Lincoln asked to be released from his engagement to Mary Todd.
 Sarah Rickard.
 On March 28, Logan & Lincoln obtained judgment for $312.09 in James Bell & Company v. John Lockridge. Speed had been a partner in Bell & Company.
 A friend of Speed's who lived in Louisville, Kentucky.