Answer:
So I never really learned about this or really about him at all. But I have heard this before.
Step-by-step explanation:
Well the whole quote is "that government of the people, by the people, for the people, shall not perish from the earth." So maybe he is saying that the government and laws made for the people made by the people shall not leave or else all is doomed. This is my opinion and I the Lincoln. Maybe to prevent more soldiers from dying. Because If I remember wasn't this for all the soldiers that died?..
Anyways have a wonderful day!! :)) <3