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

The great predominating elements of Mr. Lincoln's peculiar character were: first, his great capacity and power of reason; second, his conscience and his excellent understanding; third, an exalted idea of the sense of right and equity; fourth, his intense veneration of the true and the good. His conscience, his heart and all the faculties and qualities of his mind bowed submissively to the despotism of his reason. He lived and acted from the standard of reason — that throne of logic, home of principle — the realm of Deity in man. It is from this point Mr. Lincoln must be viewed. Not only was he cautious, patient, and enduring; not only had he concentration and great continuity of thought; but he had profound analytical power. His vision was clear, and he was emphatically the master of statement. His pursuit of the truth, as before mentioned, was indefatigable. He reasoned from well-chosen principles with such clearness, force, and directness that the tallest intellects in the land bowed to him. He was the strongest man I ever saw, looking at him from the elevated standpoint of reason and logic. He came down from that height with irresistible and crashing force. His Cooper Institute and other printed speeches will prove this; but his speeches before the courts -especially the Supreme Court of Illinois--if they had been preserved, would demonstrate it still more plainly. Here he demanded time to think and prepare. The office of reason is to determine the truth. Truth is the power of reason, and Lincoln loved truth for its own sake. It was to him reason's food.