William Safire has a worthy note on the Gettysburg Address in Sunday’s New York Times Magazine that is worth a read. Also note Ken Masugi’s addition at The Remedy:

"While it’s good that William Safire uses his Feb. 9 Sunday NY
Times Magazine ’On Language’ column to discuss the
Gettysburg Address, it’s too bad that he didn’t note that
Lincoln’s dating of the nation’s age comes from the 90th
Psalm, in the language of the King James Bible, which dates
a man’s years as at most four score-- to live longer is to risk
decrepitude. The Civil War is America’s ’four score and
seven’-- is America ready for the grave? That is the
Lincoln’s challenge-- to make a free nation last longer than a
human lifespan."