“I am a slow walker, but I never walk back”

U.S. President Abraham Lincoln (1809-1865) issued the Emancipation Proclamation on January 1, 1863. The following anecdote appeared in a January 1864 newspaper:
 
“Mr. Lincoln, when asked recently if the emancipation proclamation was a finality, replied—‘I am a slow walker, but I never walk back.’”
 
Lincoln was saying that he was a “slow walker” (made progress slowly), but that he didn’t “walk back” (go back on the progress that was made). The “walking” was used as a metaphor.
 
The saying was often repeated by American jurist and politician Earl Warren (1891-1974). Warren popularized the slight misquote (of the last word), “I am a slow walker, but I never walk backwards.”
   
 
Wikipedia: Abraham Lincoln
Abraham Lincoln (February 12, 1809 – April 15, 1865) was the 16th President of the United States, serving from March 1861 until his assassination in April 1865. Lincoln led the United States through its Civil War—its bloodiest war and its greatest moral, constitutional and political crisis. In doing so, he preserved the Union, abolished slavery, strengthened the federal government, and modernized the economy.
     
14 January 1864, Daily Commercial Register (Sandusky, OH), “Gleanings from the Mails,” pg. 2, col. 1:
Mr. Lincoln, when asked recently if the emancipation proclamation was a finality, replied—“I am a slow walker, but I never walk back.”
 
Chronicling America
22 January 1864, Fremont (OH) Journal, pg. 3, col. 5:
Mr. Lincoln, when asked recently if the emancipation proclamation was a finality, replied—“I am a slow walker, but I never walk back.”
 
13 February 1952, Sacramento (CA) Bee, “Warren Stresses Need Of Social Progress In His Lincoln Day Address In Boston,” pg. 8, col. 8:
“We must move forward, in the spirit of evolution and progress.”
 
That, (Earl—ed.) Warren stated pointedly, was the spirit of Abraham Lincoln, who said:
 
I am a slow walker but I never walk backwards.
   
Google Books
The Saturday Evening Post
Volume 227
1954
Pg. 53:
Perhaps his (Earl Warren of the U.S. Supreme Court—ed.) attitude is best described in his own favorite quotation from Abraham Lincoln: “I am a slow walker, but I never walk backwards.”
 
Google Books
20,000 Quips & Quotes
By Evan Esar
New York, NY: Barnes & Noble Books
1995, ©1968
Pg. 850:
I am a slow walker, but I never walk backwards. —Lincoln
 
Google Books
Chief Justice:
A Biography of Earl Warren
By Ed Cray
New York, NY: Simon & Schuster
1997
Pg. 142:
Criticized for unhurried decision making, Warren retorted with Abraham Lincoln’s quip: “I’m a slow walker, but I never walk backwards.”