Hint: It was falsely attributed to him
Some years ago, in troubled times, I found this prayer by Bl. John Henry Newman:
die Zeit ist voller Bedrängnis,
die Sache Christi liegt wie im Todeskampf.
Und doch – nie schritt Christus mächtiger durch diese Erdenzeit,
nie war sein Kommen deutlicher,
nie seine Nähe spürbarer,
nie sein Dienst köstlicher als jetzt.Darum lasst uns in diesen Augenblicken des Ewigen,
zwischen Sturm und Sturm,
in der Erdenzeit zu Dir beten:O Gott,
Du kannst das Dunkel erleuchten,
Du kannst es allein!
(Kardinal John Henry Newman)
the time is full of distress,
the cause of Christ is like in agony.
And yet – never did Christ walk more powerfully through this time on earth,
Never was His coming clearer
never His proximity more noticeable,
never His service more precious than now.
Let us then in these moments of the Eternal,
in this time on Earth pray to you:
You can illuminate the darkness,
You can do it alone!(Cardinal John Henry Newman)
It gave me a lot of peace, and took me on a path of discovery, since a friend had already suggested that I read his autobiography “Apologia pro vita sua”. Within, I learned to know a personality who in the depths of his heart was always reaching for the truth. He was someone with a profound piety, the gift of friendship and pastoral care, apostolic zeal, and a high intellectual capacity. He started out as an Anglican clergyman, where he wrote the wonderful poem known to Anglicans and Catholics alike entitled, “Lead, kindly light”, when feeling lonely on his way back to England from Rome. Upon his return from this
journey, he founded the Oxford movement (also called “Tractarians”), which tried to restore the original impetus of the Anglican church, and recover its roots in early Christianity. This movement persists today in Ango-Catholic communities. He realized over time that the authorities in the Anglican Church were turning to a more Protestant stance as years went by. In 1842, he laid down his obligation to his Anglican parish, and by October 1845 he was received into the Catholic Church. This step was not an easy one for him. He states that he literally “wrote himself into the Catholic Church” by examining Church history, until he had the clarity he needed to know that this was the truth he had been looking for years. He went to Rome, was ordained a Catholic priest in 1847, and came back to England to establish the first Oratory of St. Philipp Neri in England. A few years later he was asked to become the Rector of the new Catholic University in Ireland. This was not a successful endeavor, but did bring us another wonderful book: “The Idea of a University”. He then returned to the Oratory in Birmingham. In 1879, he was made Cardinal by Pope Leo XIII.
All my attempts to locate this wonderful prayer in the original English failed utterly, until Pater Edmund Waldstein, OCD (just around the corner from Vienna, in Heiligenkreuz)  gave me the hint I needed: the prayer was not written by Cardinal Newman but inspired by him, and incorporates several lines from his work.
Curiosity then took me to the Theological Library of the Vienna University to find an article  from 1944:
|Dieses Gebet ist nicht von Newman. Von ihm stammt nur die Schlußzeile: „O Gott, Du kannst das Dunkel erleuchten, Du kannst es allein“ (vgl. „Gebete und Betrachtungen“). Was vor diesen Worten steht, ist das Vorwort, das Johannes Dierkes seinem Buch „Gedanken und Gebete im Christuslicht“ (Paderborn 1936) mitgab. Durch irgendein Geschick oder Mißgeschick wurde das ganz Gebet irrtümlicherweise Newman zugeschrieben.
(Ich verdanke diesen Hinweis J. Gülden  vom Leipziger Oratorium)
|This prayer is not written by Newman. His is only the last line: ” O God, You can illuminate the darkness, You can do it alone ” (see “Prayers and Meditations”) Everything before these words is from the preface which Johannes Dierkes wrote to his book “Thoughts and Prayers the light of Christ “(Paderborn 1936). By some fate or misfortune the whole prayer was erroneously attributed to Newman.
(I am endebted to J. Gülden  from the Oratorium in Leipzig for this hint)
This prayer for the Church and Her people likely spread quickly among Catholics during the Nazi regime. You can find it in letters that soldiers wrote to others from the war front . Cardinal Franz König from Vienna recommended it to the Catholic youth , and even Pope Pius XII once mentioned it in a letter  to the Bishop of Trier:
|Wir schließen mit dem Worte aus dem Gebet Kardinal Newman’s, das du angeführt hast, mit dem Worte, dass nie der Dienst Christi köstlicher war als jetzt.9 Kardinal Newman konnte nicht ahnen, wie noch viel mehr als für seine Zeit dieses Wort und sein ganzes Gebet für unsere Tage gelten würde. Wir hoffen und beten, dass alle deiner Hut anvertrauten Gläubigen dieses Wort an sich wahr machen, und spenden in solcher Zuversicht dir, ehrwürdiger Bruder, deinem Klerus und deinen Diözesanen aus der Fülle des Herzens und in besonderer Liebe den erbetenen Apostolischen Segen.
Aus dem Vatikan, den 20. Februar 1942
|We conclude with the words from the prayer of Cardinal Newman, which you have referred to, that the service of Christ was never more delicious than now.9 Cardinal Newman could not have foreseen, that this Word and his whole prayer would apply for our days even much more than for his time. We hope and pray that all of your faithful will make this word true for themselves, and in such confidence will give you, venerable brother, your clergy and the faithful in your diocese from the fullness of heart and in special love the apostolic blessing requested.
From the Vatican, February 20, 1942
In the footnote mentioned in the papal letter, the editors comment that the Bishop had referred to the prayer in German, but they were unable to locate the source of the text .
We now know why!
The expression “the cause of Christ is like in agony” comes from the final paragraph of “Lectures on the Prophetical Office of the Church” (1837):
But in truth the whole course of Christianity from the first, when we come to examine it, is but one series of troubles and disorders. Every century is like every other, and to those who live in it seems worse than all times before it. The Church is ever ailing, and lingers on in weakness, “always bearing about in the body the dying of the Lord Jesus, that the life also of Jesus might be made manifest in her body.” Religion seems ever expiring, schisms dominant, the light of Truth dim, its adherents scattered. The cause of Christ is ever in its last agony, as though it were but a question of time whether it fails finally this day or another. The Saints are ever all but failing from the earth, and Christ all but coming; and thus the Day of Judgment is literally ever at hand; and it is our duty ever to be looking out for it, not disappointed that we have so often said, “now is the moment,” and that at the last, contrary to our expectation, Truth has somewhat rallied. Such is God’s will, gathering in His elect, first one and then another, by little and little, in the intervals of sunshine between storm and storm, or snatching them from the surge of evil, even when the waters rage most furiously. [….] God alone knows the day and the hour when that will at length be, which He is ever threatening; meanwhile, thus much of comfort do we gain from what has been hitherto,—not to despond, not to be dismayed, not to be anxious, at the troubles which encompass us. They have ever been; they ever shall be; they are our portion. “The floods are risen, the floods have lift up their voice, the floods lift up their waves. The waves of the sea are mighty, and rage horribly; but yet the Lord, who dwelleth on high, is mightier.” 
And the last sentence “O God, You can illuminate the darkness , You can do it alone!” is taken from a collection of prayers (Prayer for the Light of Truth, :
I should like an enquirer to say continually:
O MY God, I confess that Thou canst enlighten my darkness. I confess that Thou alone canst. I wish my darkness to be enlightened. I do not know whether Thou wilt: but that Thou canst and that I wish, are sufficient reasons for me to ask, what Thou at least hast not forbidden my asking. I hereby promise that by Thy grace which I am asking, I will embrace whatever I at length feel certain is the truth, if ever I come to be certain. And by Thy grace I will guard against all self-deceit which may lead me to take what nature would have, rather than what reason approves.
… which is another beautiful prayer – this time from Blessed John Henry Newman himself.
 Pater Edmund Waldstein blogs at sancrucensis.wordpress.com
 Heinrich Fries (Tübingen), “Begegnung mit Newman: Versuch einer bibliographischen Umschau”, Theologische Revue 16 Bd 1, 15-20; 1944
 As a side-note, Joseph Gülden had a very impressive life : He was ordained as priest in 1932 and joined the Oratorians in 1934, at the Philipp Neri Oratory in Leipzig. So he knew Newman’s writings first-hand. During the Nazi Regime he was chief editor of the periodical of the Catholic Youth Organization Bund Neudeutschland until 1939 (when it was forbidden). During the war and then during the Communist regime, he was well known for his tireless and kind pastoral care for the people that needed him. Until 1979, he was also chief editor of the main weekly Catholic newspaper that was allowed by the regime to be printed – a newspaper that could only be distributed via subscription. He was also founding member of a Catholic publishing house (St. Benno) to provide profound spiritual and doctrinal foundation to the very few Catholics living in an atheist environment. Source: Joseph Gülden CO, Wikipedia
 Karl-Theodor Schleicher, Heinrich Walle. Aus Feldpostbriefen junger Christen 1939-1945. Ein Beitrag zur Geschichte der Katholischen Jugend im Felde. Franz Steiner Verlag, Stuttgart 2005
 Mgr Bornewasser a cité le texte en traduction allemande: „O Gott, die Zeit ist voller Bedrängnis, die Sache Christi liegt im Todeskampf. Und doch nie schritt Christus mächtiger durch die Erdenzeit, nie war sein Kommen deutlicher, nie seine Nähe spürbarer, nie sein Dienst köstlicher als jetzt. Darum lasst uns in diesem Augenblick des Ewigen, zwischen Sturm und Sturm, in der Erdenzeit zu Ihm beten: O Gott, Du kannst das Dunkel erleuchten, Du kannst es allein“. Nous n’avons pas pu trouver d’où ce texte était pris.
 John Henry Newman, “Lectures on the Prophetical Office of the Church” (1837)
 John Henry Newman, “Meditations and Devotions”, p 280
Picture: Kees de Kort, Seesturm