“A lawyer’s time and advice are his stock in trade” is a classic legal aphorism that is often credited to Abraham Lincoln (1809-1865), but there’s no evidence that he said it. “A lawyer’s library is his stock in trade” was cited in 1807; “A lawyer’s wits used to be an important part of his stock in trade” was cited in 1855.
 
The novel Without a Compass (1885) by Frederick B. Van Vorst contained the line, “A lawyer’s time is his stock in trade.” This line was credited to Lincoln by at least 1928.
   
“A lawyer’s time and advice are his stock in trade” appeared on cards—with an Abraham Lincoln silhouette—that the West Publishing Company gave to lawyers in the 1930s.
 
   
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1845, The Law Magazine: Or, Quarterly Review of Jurisprudence (vol. 3, no. 5), pg. 296:
A lawyer’s wits used to be an important part of his stock in trade; his brothers and uncles, and cousins are now much more instrumental to his success.
 
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Memorial of the Rev. Henry Alford, A.M.
London: Rivingtons
1855
Pg. 9:
VIII.—TO MISS SELIZA PAGET.
Temple, Nov. 18, 1807.
(...)
A lawyer’s library is his stock in trade. He cannot proceed without books.
 
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Without a Compass:
A Novel
By Frederick B. Van Vorst
New York, NY: D. Appleton and Company
1885
Pg. 120:
“But — ” began Walker-Brice, “my time is valuable.”
 
“A lawyer’s time is his stock in trade,” said Van Dorn, a little bruskly.
 
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West Publishing Company’s Docket, Volume 4
Pg. 3742:
1928
WHEN publishing in the last Docket, the resolution of the Nolan County (Tex.) Bar Association, providing for minimum charges for consultations, thereby emphasizing Lincoln’s saying that “a lawyer’s time is his stock in trade,” ...
 
15 November 1935, Greensboro (NC) Record, “Yesterday’s Footnotes” by Ted Thompson, pg. 3, col. 2:
You can pretty well tell, unless you already know, when you are entering the office of a young lawyer. On his desk, or perhaps on the nearest filing cabinet, you’ll see a framed card bearing these words:
 
“A lawyer’s time and advice are his stock in trade.”
 
Allegedly it is a Lincoln quotation. As a sort of proof, maybe, you’ll notice that the framed cards displays a silhouette of Lincoln’s head.
 
It might be added that this framed card costs nothing; the West Publishing company (law books) will give you one if you’re ready and qualified to have the gold lettering placed upon your door.
 
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The Yale Book of Quotations
Edited by Fred R. Shapiro
New Haven, CT: Yale University Press
2006
Abraham Lincoln
U.S. president, 1809-1865
Pg. 466:
A lawyer’s time and advice are his stock in trade.
Attributed in Bulletin, Lincoln National Life Foundation, 11 July 1949, Michael J. Musmanno noted in his dissenting opinion in Sterling v. Philadelphia (1954): “A study of Lincoln’s accredited writings fails to produce this aphorism. The Lincoln National Life Foundation, which makes an effort to trace the origin or supposed Lincoln sayings, reports that this one,.,,apparently came to life in a plaque produced by the Allen Smith Company in Indianapolis… (Bulletin, Lincoln National Life Foundation No. 1057, July 11, 1949.)”
 
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From Teamwork to Excellence:
Labor and Economic Factors Affecting Educators
By Sid T. Womack, Shellie L. Hanna, Stephanie Pepper, Mohamed Ibrahim and Peggy Woodall
Lanham, MD: Rowman & Littlefield Education
2014
Pg. 19:
Inside most attorneys’ offices is a plaque that says, “A lawyer’s time and advice are his stock-in-trade.” The rate that most attorneys charge is a sharp reminder to those who are negligent in reading the plaque.