„Man is fulfilled only when he ceases to be man.“

„Man is free, but his freedom ceases when he has no faith in it“

—  Giacomo Casanova Italian adventurer and author from the Republic of Venice 1725 - 1798

.
Memoirs (trans. Machen 1894), book 1, Preface http://etext.library.adelaide.edu.au/c/casanova/c33m/preface2.html
Referenced

„Man only plays when in the full meaning of the word he is a man, and he is only completely a man when he plays.“

—  Friedrich Schiller, book On the Aesthetic Education of Man

Letter 15
On the Aesthetic Education of Man (1794)

„Work is not a constraint. Man's activity provides his true fulfilment. True fulfilment however, can only be achieved if one man is not another man's slave.“

—  Elfriede Jelinek, book Wonderful, Wonderful Times

73
Wonderful, Wonderful Times (1990)

„When laws, customs, or institutions cease to be beneficial to man, they cease to be obligatory.“

—  Henry Ward Beecher American clergyman and activist 1813 - 1887

Source: Life Thoughts (1858), p. 34

„I, the man of color, want only this: That the tool never possess the man. That the enslavement of man by man cease forever. That is, of one by another. That it be possible for me to discover and to love man, wherever he may be.“

—  Frantz Fanon, book Black Skin, White Masks

Source: Black Skin, White Masks

„Love ceases to be a demon only when he ceases to be a god.“

—  Denis de Rougemont Swiss writer 1906 - 1985

„A man is free when he sees clearly the fulfillment of his being and is thus capable of making the envisioned self a reality.“

—  James H. Cone American theologian 1938 - 2018

Source: Black Theology and Black Power (1969), p. 39

„Now, he no longer promises others the fulfillment of his duties, but promises himself the fulfillment of man.“

—  Martin Buber German Jewish Existentialist philosopher and theologian 1878 - 1965

Source: Between Man and Man (1965), p. 178 -->

„Difficulty attracts the characterful man, for it is by grasping it that he fulfils himself.“

—  Charles de Gaulle eighteenth President of the French Republic 1890 - 1970

La difficulté attire l'homme de caractère, car c'est en l'étreignant qu'il se réalise lui-même.
in Mémoires de guerre.
Writings

„The history of the human race is a continual struggle from darkness towards light. It is, therefore, to no purpose to discuss the use of knowledge; man wants to know, and when he ceases to do so, he is no longer man.“

—  Fridtjof Nansen Norwegian polar explorer and Nobel Peace Prize laureate 1861 - 1930

[Nansen, Fridtjof, A New Route to the North Pole, https://books.google.com/books?id=KPoLAAAAMAAJ&pg=PA693, 11, August 1891, The Forum, 693–709]

„Man is by nature a lover. Only he has yet to discover the real thing to love. This quest awakens him to the fulfillment of his real Self.“

—  Sri Chinmoy Indian writer and guru 1931 - 2007

The Wings of Joy (1997)

„The social, friendly, honest man,
Whate'er he be,
'Tis he fulfills great Nature's plan,
And none but he!“

—  Robert Burns Scottish poet and lyricist 1759 - 1796

Second Epistle to J. Lapraik, st. 15 (1786).

„When a man, however passively, becomes an obstacle to the fulfillment of a woman's desires, he becomes an odious thing in her eyes, - or will, given time enough.“

—  Theodore Dreiser, book Sister Carrie

Source: Sister Carrie

„Prayer will make a man cease from sin, or sin will entice a man to cease from prayer.“

—  John Bunyan English Christian writer and preacher 1628 - 1688

„The only time a woman really succeeds in changing a man is when he's a baby.“

—  Natalie Wood American actress 1938 - 1981

„The man who has ceased to fear has ceased to care.“

—  F. H. Bradley British philosopher 1846 - 1924

No. 63.
Aphorisms (1930)

„[T]he task of science can never end till man ceases to be, till history is no longer made, and development itself ceases.“

—  Karl Pearson, book The Grammar of Science

Introductory
The Grammar of Science (1900)

„And ah for a man to arise in me,
That the man I am may cease to be!“

—  Alfred, Lord Tennyson British poet laureate 1809 - 1892

Part I, section x, stanza 6
Maud; A Monodrama (1855)

„When one confesses to an act, one ceases to be an actor in it and becomes its witness, becomes a man that observes and narrates it and no longer the man that performed it.“

—  Jorge Luis Borges Argentine short-story writer, essayist, poet and translator, and a key figure in Spanish language literature 1899 - 1986

"Guayaquil", in Brodie's Report (1970); tr. Andrew Hurley, Collected Fictions (1998)