April 22d 1861
With feelings of deep regret, I respectfully tender my commission in the Army of the United States.
The feelings which impel me to this act are, I believe, understood by the Hon: Secretary of War.
I hope that long service, with some labor, hardship, danger & loss of blood, may give me some claim to ask the early consideration of this communication.
Your obt servt
J. E. Johnston, Qr Mr Genl
Col. L. Thomas
Source: War Department. The Adjutant General's Office, Series: Letters Received, 1805 - 1889, Record Group 94: Records of the Adjutant General's Office, 1762 - 1984, US National Archives identifier 3819339. Link here.
[US Quartermaster General Joseph Eggleston Johnston (1807-1891), soon to be a full Confederate General
Colonel Lorenzo Thomas (1804-1875), Adjutant General of the US Army
Secretary of War = Simon Cameron (1799-1889), from 1861 until early 1862. Notations on the other side of this document indicate that it was approved on the same date. Johnston was the highest ranking US Army officer to join the Confederate Army]