Oh no, Motley, you just revealed your  historical problem!
Lincoln never "told Fredrick Douglas in front of 12,000 people" anything.
He was speaking to  STEPHEN Douglas! (whom he referred to  as "Judge Douglas.")
Frederick Douglass was the great black civil rights leader and former slave, who had a rather balanced view of Lincoln, seeing him as being too slow at first but later recognizing that he had done what he had to do to end slavery which was, along  with saving the Union, his major goal.  He essentially was saying "for a white guy Lincoln was pretty great."
But then, Motley, Douglas is so confusing-- you have Douglas County named for this very Stephen Douglas though it was David Douglas who  discovered the sugar pine there which led to the Douglas Fir being named for him. (David Douglas)
Regards, Douglas