Mormon History, Aug 19, 1846

Letter to the Mormon Battalion-- This letter and the one which follows it under a date of August 20th, both addressed to Captain Jefferson Hunt and the Officers and Soldiers of the Mormon Battalion, are the official instructions of the Presiding Council of the Church as the Battalion left for its duty to the United States government and to the body of the Saints. Interesting are the instructions: "If you are sick, live by faith, and let the surgeon's medicine alone if you want to live, using only such herbs and mild food as are at your disposal. If you give heed to this counsel you will prosper; but if not, we cannot be responsible for the consequences." In the second letter the Battalion was told among other significant things that: ". . . we give counsel upon counsel because it is our duty, and because we love you, and want to exalt you to the highest glory, and not because we have no confidence in you, far from it." This second letter is a classic as advice to young soldiers going into the service of their country for the first time, later First Presidencies at the beginning of World War I and World War II issued equally inspired counsel to the young L.D.S. soldiers going into service for the first time in those later wars. See especially the Messages of President Heber J. Grant and counselors read at the April and October Conferences, 1942.
Camp of Israel, Omaha Nation, Cutler's Park, August 19, 1846. To Captain Jefferson Hunt and the Officers, and Soldiers of the Mormon Battalion:- We have the opportunity of sending to Fort Leavenworth this morning, by Dr. Reed, a package of twenty-five letters, which we improve, with this word of counsel to you all: If you are sick, live by faith, and let surgeon's medicine alone if you want to live, using only such herbs and mild foods as are at your disposal. If you give heed to this counsel, you will prosper; but if not, we cannot be responsible for the consequences. A hint to the wise is sufficient.
In behalf of the Council, BRIGHAM YOUNG, President. W. Richards, Clerk. {1846-August 19-RCH 2:239}

[source: Clark, James R., Messages of the First Presidency (6 volumes)]