Everyone is for liberty, but not everyone agrees what liberty is. In Lincoln's day, some people thought liberty meant freedom of slaves from bondage, but others argued that liberty meant the freedom to hold slaves if they wanted.
Here is what Lincoln said:
Words are often more ambiguous than most of us realize. Debates and disagreements over the meaning of words can lead to conflict, sometimes violent conflict, and sometimes, as in Lincoln's day, a long and bloody civil war.The world has never had a good definition of liberty, and the American people, just now, are much in need of one. We all declare for liberty; but in using the same word we do not all mean the same thing. With some the word liberty may mean for each man to do as he pleases with himself, and the product of his labor; while with others the same word may mean for some men to do as they please with other men, and the product of other men’s labor. Here are two, not only different, but incompatible things, called by the same name — liberty. And it follows that each of the things is, by the respective parties, called by two different and incompatible names — liberty and tyranny.The shepherd drives the wolf from the sheep’s throat, for which the sheep thanks the shepherd as a liberator, while the wolf denounces him for the same act as the destroyer of liberty, especially as the sheep was a black one. Plainly the sheep and the wolf are not agreed upon a definition of the word liberty; and precisely the same difference prevails today among us human creatures, even in the North, and all professing to love liberty. Hence we behold the processes by which thousands are daily passing from under the yoke of bondage, hailed by some as the advance of liberty, and bewailed by others as the destruction of all liberty.