“Art is long, life short, judgment difficult, opportunity transient. To act is easy, to think is hard; to act according to our thought is troublesome. Every beginning is cheerful: the threshold is the place of expectation. The boy stands astonished, his impressions guide him: he learns sportfully, seriousness comes on him by surprise. Imitation is born with us: what should be imitated is not easy to discover. The excellent is rarely found, more rarely valued. The height charms us, the steps to it do not: with the summit in our eye, we love to walk along the plain. It is but a part of art that can be taught: the artist needs it all. Who knows it half, speaks much, and is always wrong: who knows it wholly, inclines to act, and speaks seldom or late. The former have no secrets and no force : the instruction they can give is like baked bread, savory and satisfying for a single day; but flour cannot be sown, and seed-corn ought not to be ground. Words are good, but they are not the best. The best is not to be explained by words. The spirit in which we act is the highest matter. Action can be understood and again represented by the spirit alone. No one knows what he is doing while he acts aright, but of what is wrong we are always conscious. Whoever works with symbols only is a pedant, a hypocrite, or a bungler. There are many such, and they like to be together. Their babbling detains the scholar: their obstinate mediocrity vexes even the best. The instruction which the true artist gives us opens the mind; for, where words fail him, deeds speak. The true scholar learns from the known to unfold the unknown, and approaches more and more to being a master.”

The Divinity College Address (1838)

in The Erasmus Reader (1990), p. 130.
Ciceronianus (1528)

National Socialism Now, pamphlet issued by the National Socialist League c. 1938.

Source: Winnie-the-Pooh

The Decay of Lying (1889)

Source: Interview by Prince Rama Varma "There's no one way to teach".

As quoted in Great Britain and the East, Vol. 61, Issues 1727-1742 (1944), p. 19 https://books.google.com/books?id=94AyAQAAIAAJ&q=%22To+understand+is+difficult;+to+act+is+easy%22&dq=%22To+understand+is+difficult;+to+act+is+easy%22&hl=en&sa=X&ved=0ahUKEwiey5eF27fXAhWMHpQKHS3JCYAQ6AEILDAB

Part V, Prop. XLII, Scholium
Ethics (1677)

The Human Comedy (1943)
Context: Death is not an easy thing for anyone to understand, least of all a child, but every life shall one day end. But as long as we are alive, as long as we are together, as long as two of us are left, and remember him, nothing in the world can take him from us. His body can be taken, but not him. You shall know your father better as you grow and know yourself better. He is not dead, because you are alive. Time and accident, illness and weariness took his body, but already you have given it back to him, younger and more eager than ever. I don't expect you to understand anything I'm telling you. But I know you will remember this — that nothing good ever ends. If it did, there would be no people in the world — no life at all, anywhere. And the world is full of people and full of wonderful life.