Here are two from The Consolation of Philosophy by Boethius.
"But folly, driven by self-deception, cannot change the merits of the case; nor can I think it right either to hide the truth or concede a lie."
"How could hostile fury drive men to take up arms when war offers no reward for gaping wounds except the blood that was spilled?"
I have been re-reading Story of a Soul by St. Thérèse of Lisieux, who has some comforting words.
"But when God stretches out His hand to ask, His hand is never empty, and His intimate friends can draw from Him the courage and strength they need."
"Ah! Poor women, how they are misunderstood! And yet they love God in much larger numbers than men do and during the Passion of Our Lord, women had more courage than the apostles since they braved the insults of the soldiers and dared to dry the adorable Face of Jesus. It is undoubtedly because of this that He allows misunderstanding to be their lot on earth, since He chose it for Himself."
And a few miscellaneous quotations:
"Nor love thy life, nor hate; but what thou liv'st Live well; how long or short permit to Heaven." (St. Michael, in John Milton's Paradise Lost)
"There are some who desire knowledge merely for its own sake; and that is shameful curiosity. And there are others who desire to know, in order that they may themselves be known; and that is vanity, disgraceful too. Others again desire knowledge in order to acquire money or preferment by it; that too is a discreditable quest. But there are also some who desire knowledge, that they may build up the souls of others with it; and that is charity. Others, again, desire it that they may themselves be built up thereby; and that is prudence. Of all these types, only the last two put knowledge to the right use." (St. Bernard, Sermon on the Canticle of Canticles)
"God accepts our desires as though they were a great value. He longs ardently for us to desire and love him. He accepts our petitions for benefits as though we were doing him a favor. His joy in giving is greater than ours in receiving. So let us not be apathetic in our asking, nor set too narrow bounds to our requests; nor ask for frivolous things unworthy of God's greatness." (St. Gregory Nazianzen)
"Who could know that, at a certain point in time, when it was very hard for you, you said through tears that you love Him and always want to love Him?" (Fr. Tadeusz Dajczer)