In this context, it means "instead."

Ah, Lincoln's Gettysburg Address. If you look up RATHER, any of the first three definitions might apply . . . 'more properly, with better reason' etc. RATHER is contrasting WE (Lincoln and the audience) with the people who actually fought and died in the battle, as he refers to in the second sentence of the paragraph.

Rather = preferably

من الأفضل