“In truth, O judges, while I wish to be adorned with every virtue, yet there is nothing which I can esteem more highly than being and appearing grateful. For this one virtue is not only the greatest, but is also the parent of all the other virtues.”

1920s, The Prospects of Industrial Civilization (1923)
Context: The governors of the world believe, and have always believed, that virtue can only be taught by teaching falsehood, and that any man who knew the truth would be wicked. I disbelieve this, absolutely and entirely. I believe that love of truth is the basis of all real virtue, and that virtues based upon lies can only do harm.

Song 22: "Against Pride in Clothes".
1710s, Divine Songs Attempted in the Easy Language of Children (1715)

"Exeat"
The Best Beast (1966)

Of Adversity
Essays (1625)
Context: The virtue of prosperity, is temperance; the virtue of adversity, is fortitude; which in morals is the more heroical virtue. Prosperity is the blessing of the Old Testament; adversity is the blessing of the New; which carrieth the greater benediction, and the clearer revelation of God's favor. Yet even in the Old Testament, if you listen to David's harp, you shall hear as many hearse-like airs as carols; and the pencil of the Holy Ghost hath labored more in describing the afflictions of Job, than the felicities of Solomon. Prosperity is not without many fears and distastes; and adversity is not without comforts and hopes.

Speech to the National Convention, (5 February 1794), as quoted in The Bolshevik Revolution, 1917-1923, Vol. 1 (1951) by Edward Hallett Carr, p. 154
Variant translations:
The attribute of popular government in a revolution is at one and the same time virtue and terror. Terror without virtue is fatal; virtue without terror is impotent. The terror is nothing but justice, prompt, severe, inflexible; it is thus an emanation of virtue.
As quoted in Red Star Over Southern Africa (1988) by Morgan Norval, p. xvi
If the mainspring of popular government in peace time is virtue, its resource during a revolution is at one and the same time virtue and terror; virtue, without which terror is merely terrible; terror, without which virtue is simply powerless.
As quoted in Rousseau, Robespierre and English Romanticism (1999) by Gregory Dart
Terror is nothing other than justice, prompt, severe, inflexible; it is therefore an emanation of virtue; it is not so much a special principle as it is a consequence of the general principle of democracy applied to our country's most urgent needs.
Original French: La terreur n'est autre chose que la justice prompte, sévère, inflexible; elle est donc une émanation de la vertu ; elle est moins un principe particulier, qu’une conséquence du principe général de la démocratie, appliqué aux plus pressants besoins de la patrie.
From Sur les principes de morale politique http://www.royet.org/nea1789-1794/archives/discours/robespierre_principes_morale_politique_05_02_94.htm

"Quotes", The Educated Imagination (1963), Talk 6: The Vocation of Eloquence

i.e., self-control or moderation.
Source: The First Step (1892), Ch. VIII

30a–b
Plato, Apology