My understanding is there is some doubt put forward as to whether Abe Lincoln was the original source of the quote, (attributed here to W.F. Buckley jr.), a quote which has been modified through time, and reused by others. The basis of some doubt us that the quote is clearly not of Lincolns style. Another source of such doubt is Ralph Keyes' book, The Quote Verifier that provides an earlier source:

""In late 1863 a spoofy newspaper advertisement for [Artemus] Ward included this testimonial: "I have never heard any of your lectures, but from what I can learn I should say that for people who like the kind of lectures you deliver, they are just the kind of lectures such people like""