“Every line of it is replete with wisdom”
Referring to the importance of well trained militia amidst the populations of the states and their preferability to standing armies, in a letter to James Monroe (19 June 1813), published Thomas Jefferson to James Monroe, 19 June 1813 https://founders.archives.gov/documents/Jefferson/03-06-02-0188; though most publications of the letter since the 1830s usually provide a date of 18 June 1813, the actual manuscript seems to distinctly read "June 19 '13" http://memory.loc.gov/master/mss/mtj/mtj1/046/0800/0894.jpg; a portion of this statement is sometimes paraphrased: "Every citizen should be a soldier."
1810s
Context: !-- Dear Sir,—Your favors of the 7th and 16th are received, and --> I now return you the memoir … I am much gratified by its communication, because, as the plan appeared in the newspapers soon after the new Secretary of War came into office, we had given him the credit of it. Every line of it is replete with wisdom; and we might lament that our tardy enlistments prevented its execution, were we not to reflect that these proceeded from the happiness of our people at home. It is more a subject of joy that we have so few of the desperate characters which compose modern regular armies. But it proves more forcibly the necessity of obliging every citizen to be a soldier; this was the case with the Greeks and Romans, and must be that of every free State. Where there is no oppression there will be no pauper hirelings. We must train and classify the whole of our male citizens, and make military instruction a regular part of collegiate education. We can never be safe till this is done.
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Thomas Jefferson 456
3rd President of the United States of America 1743–1826Related quotes
Book III. Concerning Petitions and Axioms.
The Philosophical and Mathematical Commentaries of Proclus on the First Book of Euclid's Elements Vol. 2 (1789)

Dijkstra (1988) " On the cruelty of really teaching computing science http://www.cs.utexas.edu/users/EWD/transcriptions/EWD10xx/EWD1036.html (EWD1036).
1980s

“On every thorn, delightful wisdom grows, In every rill a sweet instruction flows.”

“Every crowd has a silver lining.”
The first appearance of this quote in print was in the July 1908 issue http://books.google.com/books?id=3StKAQAAMAAJ&q=%22Every+crowd+has+a+silver+lining%22&pg=PA423#v=onepage of the journal Profitable Advertising under the heading "Modernized Maxims." It next appeared in the June 1911 issue http://books.google.com/books?id=iKZHAAAAYAAJ&q=%22Every+crowd+has+a+silver+lining%22&pg=PA32#v=onepage of The Philistine where Elbert Hubbard labeled it: "motto for a hotel-keeper." In the 1920s http://books.google.com/books?id=FBrnAAAAMAAJ&q=%22Every+crowd+has+a+silver+lining%22&pg=PA2#v=onepage, it was published with the label: "Pickpocket's motto." The attribution to P.T. Barnum didn't appear in print until a 1934 article http://books.google.com/books?id=HSIYAQAAIAAJ&q=%22Every+crowd+has+a+silver+lining%22&pg=PA14#v=onepage in Reader's Digest.
Misattributed

“Every silver lining obscures a cloud.”
Ron English's Fauxlosophy (2016)

“To attain knowledge, add things every day.
To attain wisdom, remove things every day.”
Source: Tao Te Ching, Ch. 48

Lee Scoresby and Stanislaus Grumman in Ch. 14 : Alamo Gulch
His Dark Materials, The Subtle Knife (1997)
Context: "You have a strange way about you, Dr. Grumman. You ever spend any time among the witches?"
"Yes," said Grumman. "And among academicians, and among spirits. I found folly everywhere, but there were grains of wisdom in every stream of it. No doubt there was much more wisdom that I failed to recognize. Life is hard, Mr. Scoresby, but we cling to it all the same."
"And this journey we're on? Is that folly or wisdom?"
"The greatest wisdom I know."
"Tell me again what your purpose is. You're going to find the bearer of this subtle knife, and what then?"
"Tell him what his task is."
"And that's a task that includes protecting Lyra," the aeronaut reminded him.
"It will protect all of us."

As quoted in Bird : The Legend Of Charlie Parker (1977) by Robert George Reisner, p. 27