On the night of June 6, 1944, President Roosevelt went on national radio to discuss the invasion of Normandy — D-Day — with the American people.
President Franklin D. Roosevelt, “D-Day Prayer” (June 6, 1944)
Almighty God: Our sons, pride of our Nation, this day have set upon a mighty endeavor, a struggle to preserve our Republic, our religion, and our civilization, and to set free a suffering humanity.
Lead them straight and true; give strength to their arms, stoutness to their hearts, steadfastness in their faith.
They will need Thy blessings. Their road will be long and hard. For the enemy is strong. He may hurl back our forces. Success may not come with rushing speed, but we shall return again and again; and we know that by Thy grace, and by the righteousness of our cause, our sons will triumph.
They will be sore tried, by night and by day, without rest-until the victory is won. The darkness will be rent by noise and flame. Men’s souls will be shaken with the violences of war.
His address took the form of this prayer. (Full text from Franklin D. Roosevelt Presidential Library and Museum)
The day before, future president Dwight D. Eisenhower, addressed the troops of the Allied Expeditionary Force and told them,
The hopes and prayer of liberty-loving people everywhere march with you.