The poem is one a visitor to the cemetery heard Lincoln recite to himself on one of his visits to the graves. I can't begin to match its eloquence so I won't even try.
How Sleep the Brave
William Collins. 1721–1759
HOW sleep the brave, who sink to rest
By all their country's wishes blest!
When Spring, with dewy fingers cold,
Returns to deck their hallow'd mould,
She there shall dress a sweeter sod Than Fancy's feet have ever trod.
By fairy hands their knell is rung;
By forms unseen their dirge is sung;
There Honour comes, a pilgrim grey,
To bless the turf that wraps their clay;
And Freedom shall awhile repair
To dwell, a weeping hermit, there!