“We praise loyalty, but it pays the price when it supports those whom Fortune crushes.”

Source: The Band That Played On (Thomas Nelson, 2011), p. 153

Book Sometimes you win Sometimes you Learn

Letter IV : Heloise to Abelard
Letters of Abelard and Heloise
Context: What occasion had you to praise me? praise is often hurtful to those on whom it is bestowed. A secret vanity springs up in the heart, blinds us, and conceals from us wounds that are ill cured. A seducer flatters us, and at the same time, aims at our destruction. A sincere friend disguises nothing from us, and from passing a light hand over the wound, makes us feel it the more intensely, by applying remedies. Why do you not deal after this manner with me? Will you be esteemed a base dangerous flatterer; or, if you chance to see any thing commendable in me, have you no fear that vanity, which is so natural to all women, should quite efface it? but let us not judge of virtue by outward appearances, for then the reprobates as well as the elect may lay claim to it. An artful impostor may, by his address gain more admiration than the true zeal of a saint.

Speaking on his support for President Johnson in the upcoming presidential election (17 March 1967), as quoted in "I'll Campaign For Johnson," Says Kennedy" http://archives.chicagotribune.com/1967/03/18/page/39/article/ill-campaign-for-johnson-says-kennedy

Attributed to Sun Tzu in multiple books and internet sites, but this text does not appear in The Art of War and seems to be a more recent creation.
Disputed

1920s, Process and Reality: An Essay in Cosmology (1929)

Hansard, HC 6Ser vol 191 col 413 (16 May 1991) http://www.publications.parliament.uk/pa/cm199091/cmhansrd/1991-05-16/Orals-1.html.

Reportedly first said by Holmes in a speech in 1904, alternately phrased as "Taxes are what we pay for civilized society, including the chance to insure", Compania General De Tabacos De Filipinas v. Collector of Internal Revenue, 275 U.S. 87, 100, dissenting; opinion (21 November 1927). The first variation is quoted by the IRS above the entrance to their headquarters at 1111 Constitution Avenue.
1900s

1961, Speech to Special Joint Session of Congress
Context: Military and economic assistance has been a heavy burden on our citizens for a long time, and I recognize the strong pressures against it; but this battle is far from over, it is reaching a crucial stage, and I believe we should participate in it. We cannot merely state our opposition to totalitarian advance without paying the price of helping those now under the greatest pressure. We cannot merely state our opposition to totalitarian advance without paying the price of helping those now under the greatest pressure.