“Copying is not theft
Stealing a thing leaves one less left
Copying it makes one thing more
That's what copying's for.”

Quoted in: The Artist, Vol. 93 (1978) p. 5.
1970s

Introduction
Misquoting Jesus (2005)
Context: It is one thing to say that the originals were inspired, but the reality is that we don't have the originals—so saying they were inspired doesn't help me much, unless I can reconstruct the originals. Moreover, the vast majority of Christians for the entire history of the church have not had access to the originals, making their inspiration something of a moot point. Not only do we not have the originals, we don't have the first copies of the originals. We don't even have copies of the copies of the originals, or copies of the copies of the copies of the originals. What we have are copies made later—much later. In most instances, they are copies made many centuries later. And these copies all differ from one another, in many thousands of places. As we will see later in this book, these copies differ from one another in so many places that we don't even know how many differences there are. Possibly it is easiest to put it in comparative terms: there are more differences among our manuscripts than there are words in the New Testament.

Source: An Essay on Aristocratic Radicalism (1889), p. 20

Compare: "Immature poets imitate; mature poets steal." T. S. Eliot, in Philip Massinger, in The Sacred Wood (1920)
Disputed
Variant: Good artists copy, great artists steal.

This is a favorite phrase of Jobs, but he is (mis)quoting Pablo Picasso. "Lesser artists borrow; great artists steal" is similarly attributed to Igor Stravinsky, but both sayings may well originate in T. S. Eliot's dictum http://en.wikisource.org/wiki/The_Sacred_Wood/Philip_Massinger: "Immature poets imitate; mature poets steal; bad poets deface what they take, and good poets make it into something better, or at least something different. The good poet welds his theft into a whole of feeling which is unique, utterly different than that from which it is torn."
Misattributed

Compare: "Immature poets imitate; mature poets steal." T. S. Eliot, in Philip Massinger, in The Sacred Wood (1920)
Disputed

William Burges "Art and Religion", in: The Church and the World: Essays on Questions of the Day, Orby Shipley ed., London, 1868, pp. 574-98; As cited in: John Pemble. Venice rediscovered. Clarendon Press, 16 mrt. 1995. p. 133

UTI interview (2004)
Context: The law about what is stealing is very clear. Stealing is taking something away from someone so they cannot use it. There’s no way that making a copy of something is stealing under that definition.
If you make a copy of something, you’ll be prosecuted for copyright infringement or something similar — not larceny (the legal term for stealing). Stealing, like piracy and intellectual property, is another one of those terms cooked up to make us think of intellectual works the same way we think of physical items. But the two are very different.
You can’t just punish people because they took away a “potential sale”. Earthquakes take away potential sales, as do libraries and rental stores and negative reviews. Competitors also take away potential sales.

Statement to the Associated Press (November 2003), as quoted in "DVD-copy program tweaked after court order" at CNN.com (23 February 2004) http://www.cnn.com/2004/TECH/ptech/02/23/dvd.suit.ap/