“People have (with the help of conventions) oriented all their solutions toward the easy and toward the easiest side of the easy; but it is clear that we must hold to what is difficult; everything alive holds to it, everything in Nature grows and defends itself in its own way and is characteristically and spontaneously itself, seeks at all costs to be so and against all opposition.”

Summa Contra Gentiles, III,126,3

Day of Affirmation Address (1966)
Context: All do not develop in the same manner, or at the same pace. Nations, like men, often march to the beat of different drummers, and the precise solutions of the United States can neither be dictated nor transplanted to others. What is important is that all nations must march toward increasing freedom; toward justice for all; toward a society strong and flexible enough to meet the demands of all its own people, and a world of immense and dizzying change.

The Soul of Man Under Socialism (1891)

'La vie n’est facile pour aucun de nous. Mais quoi, il faut avoir de la persévérance, et surtout de la confiance en soi. Il faut croire que l’on est doué pour quelque chose, et que, cette chose, il faut l'atteindre coûte que coûte.'
As quoted in Madame Curie : A Biography (1937) by Eve Curie Labouisse, Part 2, p. 116

A Political Obituary for Donald Trump (2020)

VIII, 35
Meditations (c. 121–180 AD), Book VIII

Source: The Happiness Project: Or Why I Spent a Year Trying to Sing in the Morning, Clean My Closets, Fight Right, Read Aristotle, and Generally Have More Fun

Day of Affirmation Address (1966)
Context: The road toward equality of freedom is not easy, and great cost and danger march alongside us. We are committed to peaceful and nonviolent change, and that is important for all to understand — though all change is unsettling. Still, even in the turbulence of protest and struggle is greater hope for the future, as men learn to claim and achieve for themselves the rights formerly petitioned from others. And most important of all, all of the panoply of government power has been committed to the goal of equality before the law, as we are now committing ourselves to the achievement of equal opportunity in fact. We must recognize the full human equality of all of our people before God, before the law, and in the councils of government. We must do this, not because it is economically advantageous, although it is; not because the laws of God command it, although they do; not because people in other lands wish it so. We must do it for the single and fundamental reason that it is the right thing to do.