Here is a fuller quotation from Lincoln's speech:
We can succeed only by concert. It is not “can any of us imagine better?” but, “can we all do better?” The dogmas of the quiet past are inadequate to the stormy present. The occasion is piled high with difficulty, and we must rise with the occasion. As our case is new, so we must think anew, and act anew. We must disenthrall ourselves, and then we shall save our country.
– Abraham Lincoln, Annual Message to Congress, Dec. 1, 1862