“This is to be observed of the Bishop of London, that, though apparently of a spirit somewhat austere, there is in his idiosyncrasy a strange fund of enthusiasm, a quality which ought never to be possessed by an Archbishop of Canterbury, or a Prime Minister of England. The Bishop of London sympathies with everything that is earnest; but what is earnest is not always true; on the contrary error is often more earnest than truth.”

Earnestness

The Last Lecture (2007)
Context: How do you get people to help you? You can’t get there alone. People have to help you and I do believe in karma. I believe in paybacks. You get people to help you by telling the truth; by being earnest. I'll take an earnest person over a hip person every day, because hip is short-term, earnest is long term.

Pap VI B 120:13 1845
1840s, The Journals of Søren Kierkegaard, 1840s

Source: Dictionary of Burning Words of Brilliant Writers (1895), P. 285.

2000s, 2003, Remarks on U.S.-British relations and foreign policy (November 2003)

Quoted in Notker's The Deeds of Charlemagne (translated 2008 by David Ganz)

Review of Historic Survey of German Poetry, interspersed with Various Translations by W. Taylor, in The Edinburgh Review Vol. LIII (1831), p. 178.
1830s
Context: A man's honest, earnest opinion is the most precious of all he possesses: let him communicate this, if he is to communicate anything. There is, doubtless a time to speak, and a time to keep silence; yet Fontenelle's celebrated aphorism, I might have my hand full of truth, and would open only my little finger, may be practiced to excess, and the little finger itself kept closed. That reserve, and knowing silence, long so universal among us, is less the fruit of active benevolence, of philosophic tolerance, than of indifference and weak conviction. Honest Scepticism, honest Atheism, is better than that withered lifeless Dilettantism and amateur Eclecticism, which merely toys with all opinions; or than that wicked Machiavelism, which in thought denying every thing, except that Power is Power, in words, for its own wise purposes, loudly believes every thing: of both which miserable habitudes the day, even in England, is wellnigh over.

1840s, Heroes and Hero-Worship (1840), The Hero as Prophet

Said by the Dewan. Modern_Mysore, Dr. B. R. Ambedkar Open University, 26 November 2013, archive.org, 201 http://archive.org/stream/modernmysore035292mbp/modernmysore035292mbp_djvu.txt,
From Modern Mysore