What idea does Lincoln defend in this passage?

To provide a precise answer, I would need to know the specific passage from Lincoln you are referring to. However, Lincoln often defended the principles of equality, democracy, and the importance of unity in his speeches and writings. He emphasized the idea that the nation was founded on the belief that all men are created equal and that the preservation of the Union was essential for the realization of these principles. If you provide the passage, I can offer a more tailored response.