"My paramount object in this struggle is to save the Union, and is not either to save or to destroy slavery. If I could save the Union without freeing any slave I would do it, and if I could save it by freeing all the slaves I would do it; and if I could save it by freeing some and leaving others alone I would also do that. What I do about slavery, and the colored race, I do because I believe it helps to save the Union; and what I forbear, I forbear because I do not believe it would help to save the Union. I shall do less whenever I shall believe what I am doing hurts the cause, and I shall do more whenever I shall believe doing more will help the cause." The Collected Works of Abraham Lincoln edited by Roy P. Basler, Volume V, "Letter to Horace Greeley" (August 22, 1862), p. 388.
"We think slavery a great moral wrong, and while we do not claim the right to touch it where it exists, we wish to treat it as a wrong in the territories, where our votes will reach it." The Collected Works of Abraham Lincoln edited by Roy P. Basler, Volume IV, "Speech at New Haven, Connecticut" (March 6, 1860), p. 16.
"Do the people of the South really entertain fears that a Republican administration would, directly, or indirectly, interfere with their slaves, or with them, about their slaves? If they do, I wish to assure you, as once a friend, and still, I hope, not an enemy, that there is no cause for such fears." The Collected Works of Abraham Lincoln edited by Roy P. Basler, Volume IV, "Letter to Alexander H. Stephens" (December 22, 1860), p. 160.
"I hold it to be a paramount duty of us in the free states, due to the Union of the states, and perhaps to liberty itself (paradox though it may seem) to let the slavery of the other states alone; while, on the other hand, I hold it to be equally clear, that we should never knowingly lend ourselves directly or indirectly, to prevent that slavery from dying a natural death---to find new places for it to live in, when it can no longer exist in the old." The Collected Works of Abraham Lincoln edited by Roy P. Basler, Volume I, "Letter to Williamson Durley" (October 3, 1845), p. 348.