What does lincoln mean when he says of the people by the people for the people?

These stirring Words have inspired whole nations. But they do not stand up to critical scrutiny - which may be why Lincoln himself did not think much of this speech, hastily put together on the train down to Gettysburg.

In particular, 'Government by the people' is quite meaningless.

It was really just a big cheer for the freeing of the slaves.