While it's true the 13th Amendment, passed after Lincoln's death, freed all slaves, the thrust of your comment, IMO, unfairly diminishes his role in the abolution of our the 'national shame'.

This from Wikipedia:

"President Lincoln took an active role to ensure its [the 13th Amend.] passage through the House by ensuring the amendment was added to the Republican Party platform for the upcoming Presidential elections. His efforts came to fruition when the House passed the bill in January 1865, by a vote of 119 to 56. The Thirteenth Amendment's archival copy bears an apparent Presidential signature, under the usual ones of the Speaker of the House and the President of the Senate."