“The safest and most suitable form of penance seems to be that which causes pain in the flesh but does not penetrate to the bones, that is, which causes suffering but not sickness. So the best way seems to be to scourge oneself with thin cords which hurt superficially, rather than to use some other means which might produce serious internal injury.”

Book III, sec. 39
History of Rome

Statistical Methods and Scientific Inference, Edinburgh: Oliver and Boyd, 1956, p. 31.
1950s

Source: Man's Search for Meaning

Source: Citadelle or The Wisdom of the Sands (1948), p. 152

As quoted by Julien Offray de La Mettrie, Man a Machine (1747) Tr. Gertrude Carman Bussey https://books.google.com/books?id=GKYLAQAAIAAJ&pg=PA125 (1912)
Pensées Philosophiques (1746)

40 Inspiring Guides to a New Life

Source: 1880s, Personal Memoirs of General U. S. Grant (1885), Ch. 67.
Context: I had known General Lee in the old army, and had served with him in the Mexican War; but did not suppose, owing to the difference in our age and rank, that he would remember me, while I would more naturally remember him distinctly, because he was the chief of staff of General Scott in the Mexican War.
When I had left camp that morning I had not expected so soon the result that was then taking place, and consequently was in rough garb. I was without a sword, as I usually was when on horseback on the field, and wore a soldier's blouse for a coat, with the shoulder straps of my rank to indicate to the army who I was. When I went into the house I found General Lee. We greeted each other, and after shaking hands took our seats. I had my staff with me, a good portion of whom were in the room during the whole of the interview.
What General Lee's feelings were I do not know. As he was a man of much dignity, with an impassible face, it was impossible to say whether he felt inwardly glad that the end had finally come, or felt sad over the result, and was too manly to show it. Whatever his feelings, they were entirely concealed from my observation; but my own feelings, which had been quite jubilant on the receipt of his letter, were sad and depressed. I felt like anything rather than rejoicing at the downfall of a foe who had fought so long and valiantly, and had suffered so much for a cause, though that cause was, I believe, one of the worst for which a people ever fought, and one for which there was the least excuse. I do not question, however, the sincerity of the great mass of those who were opposed to us.

Source: Guide for the Perplexed (c. 1190), Part III, Ch.11

In p. 166.
Sources, The Yoga Darsana Of Patanjali With The Sankhya Pravacana Commentary Of Vyasa