William H. Herndon, Jesse William Weik, Herndon's Lincoln: The True Story of a Great Life, Etiam in minimis major, The History and Personal Recollections of Abraham Lincoln by William H. Herndon, for twenty years his friend and Jesse William Weik

As illustrative of a combination in Mr. Lincoln's organization, it may be said that his eloquence lay in the strength of his logical faculty, his supreme power of reasoning, his great understanding, and his love of principle; in his clear and accurate vision; in his cool and masterly statement of principles around which the issues gather; and in the statement of those issues and the grouping of the facts that are to carry conviction to the minds of men of every grade of intelligence. He was so clear that he could not be misunderstood or long misrepresented. He stood square and bolt upright to his convictions, and anyone who listened to him would be convinced that he formed his thoughts and utterances by them. His mind was not exactly a wide, broad, generalizing, and comprehensive mind, nor yet a versatile, quick, and subtle one, bounding here and there as emergencies demanded; but it was deep, enduring, strong, like a majestic machine running in deep iron grooves with heavy flanges on its wheels.

Mr. Lincoln himself was a very sensitive man, and hence, in dealing with others, he avoided wounding their hearts or puncturing their sensibility. He was unusually considerate of the feelings of other men, regardless of their rank, condition, or station. At first sight he struck one with his plainness, simplicity of manner, sincerity, candor, and truthfulness. He had no double interests and no overwhelming