“To recognize a difficulty is not to solve it.”

Mathematical Methods in Science (1977)
Context: Even if without the Scott's proverbial thrift, the difficulty of solving differential equations is an incentive to using them parsimoniously. Happily here is a commodity of which a little may be made to go a long way.... the equation of small oscillations of a pendulum also holds for other vibrational phenomena. In investigating swinging pendulums we were, albeit unwittingly, also investigating vibrating tuning forks.<!--p.224

"The Evolution of Chastity" (February 1934), as translated in Toward the Future (1975) edited by by René Hague, who also suggests "space" as an alternate translation of "the ether."
Variants:
"One day after mastering the winds, the waves, the tides and gravity" — after all the scientific and technological achievements — "we shall harness for God the energies of love. And then, for the second time in the history of the world, man will have discovered fire."
As quoted by R. Sargent Shriver, Jr. in his speech accepting the nomination as the Democratic candidate for vice president, in Washington, D. C. (8 August 1972); this has sometimes been published as if Shriver's interjection "after all the scientific and technological achievements" were part of the original statement, as in The New York Times (9 August 1972), p. 18
What paralyzes life is lack of faith and lack of audacity. The difficulty lies not in solving problems but identifying them.
As translated in The The Ignatian Tradition (2009) edited by Kevin F. Burke, Eileen Burke-Sullivan and Phyllis Zagano, p. 86
Love is the only force which can make things one without destroying them. … Some day, after mastering the winds, the waves, the tides and gravity, we shall harness for God the energies of love, and then, for the second time in the history of the world, man will have discovered fire.
As quoted in Seed Sown : Theme and Reflections on the Sunday Lectionary Reading (1996) by Jay Cormier, p. 33
The day will come when, after harnessing space, the winds, the tides, gravitation, we shall harness for God the energies of love. And, on that day, for the second time in the history of the world, humanity will have discovered fire.
As quoted in Fire of Love : Encountering the Holy Spirit (2006) by Donald Goergen, p. 92
The day will come when, after harnessing space, the winds, the tides, gravitation, we shall harness for God the energies of love. And, on that day, for the second time in the history of the world, man will have discovered fire.
As quoted in Read for the Cure (2007) by Eileen Fanning, p. v
Context: What paralyzes life is lack of faith and lack of audacity. The difficulty lies not in solving problems but expressing them. And so we cannot avoid this conclusion: it is biologically evident that to gain control of passion and so make it serve spirit must be a condition of progress. Sooner or later, then, the world will brush aside our incredulity and take this step : because whatever is the more true comes out into the open, and whatever is better is ultimately realized. The day will come when, after harnessing the ether, the winds, the tides, gravitation, we shall harness for God the energies of love. And, on that day, for the second time in the history of the world, man will have discovered fire.

In page=89
Remembering Our Leaders: Mahadeo Govind Ranade by Pravina Bhim Sain

Review http://www.rogerebert.com/reviews/latter-days-2004 of Latter Days (13 February 2004)
Reviews, Two-and-a-half star reviews

Letter to Frénicle (1657) Oeuvres de Fermat Vol.II as quoted by Edward Everett Whitford, The Pell Equation http://books.google.com/books?id=L6QKAAAAYAAJ (1912)
Context: There is scarcely any one who states purely arithmetical questions, scarcely any who understands them. Is this not because arithmetic has been treated up to this time geometrically rather than arithmetically? This certainly is indicated by many works ancient and modern. Diophantus himself also indicates this. But he has freed himself from geometry a little more than others have, in that he limits his analysis to rational numbers only; nevertheless the Zetcica of Vieta, in which the methods of Diophantus are extended to continuous magnitude and therefore to geometry, witness the insufficient separation of arithmetic from geometry. Now arithmetic has a special domain of its own, the theory of numbers. This was touched upon but only to a slight degree by Euclid in his Elements, and by those who followed him it has not been sufficiently extended, unless perchance it lies hid in those books of Diophantus which the ravages of time have destroyed. Arithmeticians have now to develop or restore it. To these, that I may lead the way, I propose this theorem to be proved or problem to be solved. If they succeed in discovering the proof or solution, they will acknowledge that questions of this kind are not inferior to the more celebrated ones from geometry either for depth or difficulty or method of proof: Given any number which is not a square, there also exists an infinite number of squares such that when multiplied into the given number and unity is added to the product, the result is a square.

InsideOut Hudson Valley, January/February 2009

Daniel Bedingham, Detlef Dürr, GianCarlo Ghirardi, Sheldon Goldstein, Roderich Tumulka, Nino Zanghì, "Matter Density and Relativistic Models of Wave Function Collapse", J Stat Phys (2014) 154:623–631

(zh-TW) 暴雨烏雲久必晴，夜深輾轉是天明。
面臨困境憑心力，度過難關一片清。

"Patience" (忍耐)

Source: Deng Feng-Zhou, "Deng Feng-Zhou Classical Chinese Poetry Anthology". Volume 6, Tainan, 2018: 81.