What did Lincoln insist the aim of the war was?

Lincoln insisted that the war wasn't about slavery or black rights in order to retain loyalty of the remaining border states. He rather argued the aim of the war was to preserve the union.

At the outset of the Civil War, Abraham Lincoln insisted that the aim of it was to prevent the secession of the Southern states and to preserve the Union (of the North and South). He declared that he had no intention of ending slavery where it existed. In August 1862 Lincoln wrote a letter to Horace Greeley stating the following:

"My paramount object in this struggle is to save the Union, and is not either to save or destroy slavery."

Lincoln insisted that the aim of the war was to maintain the Union at all costs.