“The hourly kindness, the day’s common speech,
The habitual content of each with each
When neither soul nor body has been crossed.”

This is widely attributed to Jackson on the internet, but in research done for Wikiquote, no published source has been found. Similar remarks, "Corporations have neither bodies to be punished, nor souls to be condemned, they therefore do as they like." and "It has no soul to damn and no body to kick." have been attributed to Edward Thurlow, 1st Baron Thurlow (9 December 1731 – 12 September 1806).
Disputed

Source: Peace of Soul (1949), Ch. 1, pp. 7–8
Context: The modern man is no longer a unity, but a confused bundle of complexes and nerves. He is so dissociated, so alienated from himself that he sees himself less as a personality than as a battlefield where a civil war rages between a thousand and one conflicting loyalties. There is no single overall purpose in his life. His soul is comparable to a menagerie in which a number of beasts, each seeking its own prey, turn one upon the other. Or he may be likened to a radio, that is tuned in to several stations; instead of getting any one clearly, it receives only an annoying static.If the frustrated soul is educated, it has a smattering of uncorrected bits of information with no unifying philosophy. Then the frustrated soul may say to itself: "I sometimes think there are two of me a living soul and a Ph. D." Such a man projects his own mental confusion to the outside world and concludes that, since he knows no truth, nobody can know it. His own skepticism (which he universalizes into a philosophy of life) throws him back more and more upon those powers lurking in the dark, dank caverns of his unconsciousness. He changes his philosophy as he changes his clothes. On Monday, he lays down the tracks of materialism; on Tuesday, he reads a best seller, pulls up the old tracks, and lays the new tracks of an idealist; on Wednesday, his new roadway is Communistic; on Thursday, the new rails of Liberalism are laid; on Friday, he-hears a broadcast and decides to travel on Freudian tracks: on Saturday, he takes a long drink to forget his railroading and, on Sunday, ponders why people are so foolish as to go to Church. Each day he has a new idol, each week a new mood. His authority is public opinion: when that shifts, his frustrated soul shifts with it.

Quoted in John Poynder, Literary Extracts (1844), vol. 1, p. 268. https://archive.org/stream/literaryextracts01poynuoft#page/268/mode/2up
This is often misquoted as "Did you ever expect a corporation to have a conscience, when it has no soul to be damned, and no body to be kicked?"

Plato, Phaedo

Source: Demian (1919), p. 9. Prologue
Context: Novelists when they write novels tend to take an almost godlike attitude toward their subject, pretending to a total comprehension of the story, a man's life, which they can therefore recount as God Himself might, nothing standing between them and the naked truth, the entire story meaningful in every detail. I am as little able to do this as the novelist is, even though my story is more important to me than any novelist's is to him — for this is my story; it is the story of a man, not of an invented, or possible, or idealized, or otherwise absent figure, but of a unique being of flesh and blood. Yet, what a real living human being is made of seems to be less understood today than at any time before, and men — each one of whom represents a unique and valuable experiment on the part of nature — are therefore shot wholesale nowadays. If we were not something more than unique human beings, if each one of us could really be done away with once and for all by a single bullet, story telling would lose all purpose. But every man is more than just himself; he also represents the unique, the very special and always significant and remarkable point at which the world's phenomena intersect, only once in this way and never again. That is why every man's story is important, eternal, sacred; that is why every man, as long as he lives and fulfills the will of nature, is wondrous, and worthy of every consideration. In each individual the spirit has become flesh, in each man the creation suffers, within each one a redeemer is nailed to the cross.
Few people nowadays know what man is. Many sense this ignorance and die the more easily because of it, the same way that I will die more easily once I have completed this story.

"The Next Poem" http://www.danagioia.net/poems/thenextpoem.htm
Poetry, The Gods of Winter (1991)

Book 8, Ch. 98
variant: Not snow, no, nor rain, nor heat, nor night keeps them from accomplishing their appointed courses with all speed. (Book 8, Ch. 98)
Paraphrase: "Neither snow, nor rain, nor heat, nor gloom of night stays these couriers from the swift completion of their appointed rounds" ”
Appears carved over entrance to Central Post Office building in New York City.
The Histories

Still Falls the Rain (1940)