My favorite book that Dr. King wrote was Strength to Love. On page 52-53 of that fantastic work, Martin Luther King, Jr. writes this:
Love is the only force capable of transforming an enemy into a friend. We never get rid of an enemy by meeting hate with hate; we get rid of an enemy by getting rid of enmity. Lincoln tried to love and left for all history a magnificent drama of reconciliation. When he was campaigning for the presidency one of his arch-enemies was a man named Stanton. For some reason Stanton hated Lincoln. He used every ounce of his energy to degrade him in the eyes of the public. So deep rooted was Stanton's hate for Lincoln that he uttered unkind word about his physical appearance, and sought to embarrass him at every point with the bitterest diatribes. But in spite of this Lincoln was elected President of the United States. Then came the period when he had to select his cabinet which would consist of the persons who would be his most intimate associates in implementing his program. He started choosing men here and there for various secretaryships. The day finally came for Lincoln to select a man to fill the all-important post of Secretary of War. Can you imagine whom Lincoln chose to fill this post? None other than the man named Stanton. There was an immediate uproar in the inner circle when the news began to spread. Advisor after advisor was heard saying, "Mr. President, you are making a mistake. Do you know this man named Stanton? Are you familiar with all the ugly things he said about you? He is your enemy. He will seek to sabotage your program. Have you thought this through, Mr. President?" Mr. Lincoln's answer was terse and to the point: "Yes I know Mr. Stanton. I am aware of all the terrible things he said about me. But after looking over the nation, I find that he is the best man for the job." So Stanton became Abraham Lincoln's Secretary of War and rendered an invaluable service to his nation and to his President. Not many years later Lincoln was assassinated. Many laudable things were said about him. Even today millions of people still adore him as the greatest of all Americans. But of all the great statements made about Abraham Lincoln, the words of Stanton remain among the greatest. Standing near the dead body of the man he once hated, Stanton referred to him as one of the greatest men that ever lived and said, "He now belongs to the ages." If Lincoln had hated Stanton both men would have gone to their graves bitter enemies. But through the power of love Lincoln transformed an enemy into a friend. It was this same attitude that made it possible for Lincoln to speak a kind word about the South during the civil war when feeling was most bitter. Asked by a shocked bystander how he could do this, Lincoln said, "Madam, do I not destroy my enemies when I make them friends?"