“Through such impressions one gathers oneself, wins oneself back from the exacting multiplicity, which speaks and chatters there (and how talkative it is!), and one slowly learns to recognize the very few Things in which something eternal endures that one can love and something solitary that one can gently take part in.”

Literature and Revolution (1924), edited by William Keach (2005), Ch. 4 : Futurism, p. 120
Variants:
Art is not a mirror to hold up to society, but a hammer with which to shape it.
Remarks apparently derived from Trotsky's observations, or those he implies preceded his own, this is attributed to Bertolt Brecht in Paulo Freire : A Critical Encounter (1993) by Peter McLaren and Peter Leonard, p. 80, and to Vladimir Mayakovsky in The Political Psyche (1993) by Andrew Samuels, p. 9
Art is not a mirror held up to society, but a hammer with which to shape it.
Context: Art, it is said, is not a mirror, but a hammer: it does not reflect, it shapes. But at present even the handling of a hammer is taught with the help of a mirror, a sensitive film that records all the movements. Photography and motion-picture photography, owing to their passive accuracy of depiction, are becoming important educational instruments in the field of labor. If one cannot get along without a mirror, even in shaving oneself, how can one reconstruct oneself or one's life, without seeing oneself in the "mirror" of literature? Of course no one speaks about an exact mirror. No one even thinks of asking the new literature to have mirror-like impassivity. The deeper literature is, and the more it is imbued with the desire to shape life, the more significantly and dynamically it will be able to "picture" life.

The Art of Writing

Original: Amare vuol dire scegliere la propria parte mancante, con cui confrontarsi, rispettarsi e completarsi.
Source: prevale.net

Variant: One can give up many things for love, but one should not give up oneself.
Source: The Bane Chronicles

In a letter to her parents, Worpswede, 10 September 1899; as quoted in Voicing our visions, – Writings by women artists; ed. Mara R. Witzling, Universe New York, 1991, p. 199
1899

Source: The Myth of Sisyphus (1942), Absurd Creation, p. 83

National Book Award Acceptance Speech (1957)
Context: It is true that the poet does not directly address his neighbors; but he does address a great congress of persons who dwell at the back of his mind, a congress of all those who have taught him and whom he has admired; that constitute his ideal audience and his better self. To this congress the poet speaks not of peculiar and personal things, but of what in himself is most common, most anonymous, most fundamental, most true of all men. And he speaks not in private grunts and mutterings but in the public language of the dictionary, of literary tradition, and of the street. Writing poetry is talking to oneself; yet it is a mode of talking to oneself in which the self disappears; and the products something that, though it may not be for everybody, is about everybody.

Source: Lectures on Philosophy (1959), p. 76