w/o knowing wat course it is, here are two primary sources; both are speeches by Lincoln against slavery:
1. Lincoln, Abraham, "Peoria speech" delivered in Peoria, Illinois, October 16, 1854
2. Lincoln, Abraham, "Cooper Union speech" delivered at Cooper Union, New York City, New York, February 27, 1860
secondary sources were news article at the time or historian review of the speeches:
1. Horace White, "Lincoln Among His Friends", New York Evening Post, February 12, 1909, p. 170
2. Harold Holzer. "The Speech That Made The Man", AmericanHeritage.com (American Heritage Magazin. Winter 2010. Volume 59, Issue 4)
Primary sources give direct reference to what Lincoln had said and his arguments against slavery.