“Alas that the artist… may not content himself with the inward enjoyment of the beautiful, but must chase the fitting mystery beyond the verge of his ethereal domain, and crush its frail being in seizing it with a material grasp. Owen Warland felt the impulse to give external reality to his ideas as irresistibly as any of the poets or painters who have arrayed the world in a dimmer and fainter beauty, imperfectly copied from the richness of their visions.”

"The Artist of the Beautiful" (1844)

Die Person muß sich eine äußere Sphäre ihrer Freiheit geben, um als Idee zu sein.
Sect. 41
Elements of the Philosophy of Right (1820/1821)

Source: Learning the World (2005), Chapter 16 “The Anomalies Room” (p. 273)

Quotation made in an article published in 1914. Strauss had refused to sign the Manifesto of German artists and intellectuals supporting the German role in the war. Other signatories included Strauss' friends and colleagues, such as Max Reinhardt, Richard Dehmel, Max Liebermann, Engelbert Humperdink and Felix Wiengartner. The original article quoting Strauss was by Richard Specht, and is quoted by Romain Rolland in his diary entry, found on page 160 of Richard Strauss and Romain Rolland, edited by Rollo Myers, Calder and boyars, London, 1989.
Other sources

Source: The Picture of Dorian Gray

[2019, Esoterism as Principle and as Way, World Wisdom, 190, 978-1-93659765-9]
God, Beauty

As quoted in "Hawthorne and His Mosses" (1851) http://www.eldritchpress.org/nh/hahm.html by Herman Melville

"Talk to an Art-Union (A Brooklyn fragment)" http://www.aol.bartleby.com/229/4011.html (1839); later delivered as a lecture at the Brooklyn Art Union (31 March 1851) and printed in the Brooklyn Daily Advertizer (3 April 1851)
Context: It is a beautiful truth that all men contain something of the artist in them. And perhaps it is the case that the greatest artists live and die, the world and themselves alike ignorant what they possess. Who would not mourn that an ample palace, of surpassingly graceful architecture, fill’d with luxuries, and embellish’d with fine pictures and sculpture, should stand cold and still and vacant, and never be known or enjoy’d by its owner? Would such a fact as this cause your sadness? Then be sad. For there is a palace, to which the courts of the most sumptuous kings are but a frivolous patch, and, though it is always waiting for them, not one of its owners ever enters there with any genuine sense of its grandeur and glory.
I think of few heroic actions, which cannot be traced to the artistical impulse. He who does great deeds, does them from his innate sensitiveness to moral beauty.

Letter to his wife, reprinted in Rilke’s Letters on Cézanne (1952, trans. 1985). (October 21, 1907)
Rilke's Letters