General Robert E. Lee.

What a cruel thing is war; to separate and destroy families and friends, and mar the purest joys and happiness God has granted us in this world; to fill our hearts with hatred instead of love for our neighbours, and to devastate the fair face of this beautiful world!  I pray that, on this day when only peace and good-will are preached to mankind, better thoughts may fill the hearts of our enemies and turn them to peace. … My heart bleeds at the death of every one of our gallant men.

– Gen. Robert E. Lee to his wife on Christmas Day, two weeks after the Battle of Fredericksburg (25 December 1862).