Lincoln's hand-written reply to a petition by children to free "all the little slave children in this country" surpassed the previous record for a Lincoln manuscript -- the $3.1 million for a document sold byin March 2002.
It was purchased by an American collector bidding by telephone,said.
"Please tell these little people I am very glad their young hearts are so full of just and generous sympathy, and that, while I have not that power to grant all they ask, I trust they will remember that God has, and that, as it seems, He wills to do it," Lincoln wrote in the letter.
Sotheby's called the letter "arguably Lincoln's most personal and powerful statement on God, slavery and emancipation."
He was responding to a petition signed by 195 children.
In 1862 and 1863, Lincoln signed two executive orders known together as the, which declared free slaves held in some Confederate states. The , which formally abolished slavery was ratified in December 1865, eight months after Lincoln's assassination.
The letter was the centerpiece of an auction entitled "Presidential and Other American Manuscripts from the Dr. Robert Small Trust."
(Reporting by Daniel Trotta, editing by Patricia Zengerle)