This is a personal choice of quotes by artists and others on art and motivation. The newest additions are at the top! I can’t specify all the sources, but I expect google can!

I had two reasons for choosing them. Either I admire the courage, audacity and/or wisdom of what these people said, or I feel they have personal relevance for me!
So I do not apologize for any omissions and contradictions. We all contradict ourselves at times. Maybe artists do this less than other mortals. Who knows? Other interesting quotes and articles can be found here.
 

NEW

One works because I suppose it is the most interesting thing one knows to do. The days one works are the best days. On the other days one is hurrying through the other things one imagines one has to do to keep one's life going. You get the garden planted the roof fixed. You take the dog to the vet. You spend the day with a friend. You learn to make a new kind of bread. You hunt up photographs for someone who thinks he needs them. You certainly have to do the shopping. You may even enjoy doing such things. You think they have to be done. You even think that you have to have some visitors or take a trip to keep from getting queer living alone with just two chows. But all day you wait for the time you can get at the paintings again because that is the high spot-in a way it is what you do the other things for... The painting is like a thread that runs through all the reasons, all the other things that makes one's life.
Georgia O'Keeffe
 

I’m not an abstractionist. I’m not interested in the relationship of color or form or anything else. I’m interested only in expressing basic human emotions: tragedy, ecstasy, doom, and so on.
Mark Rothko

Painting is an essentially concrete art and can only consist of the representation of real and existing things. It is a completely physical language, the words of which consist of all visible objects. An object which is abstract, not visible, non-existent, is not within the realm of painting.
Gustave Courbet

I’m not so involved in description because I think that the greatest sin an artist can be accused of is telling people things that they already know. And you can write that down and put it in italics. Our aim as artists is to use ourselves as agents for expanding possibilities; and if you’re just doing something that’s conventional and everyday, you’re not doing it right. Of course, we constantly struggle against our own conventions because that’s one of our worst difficulties—trying to avoid doing something that we already know how to do.
Wolf Kahn

You don’t have to embrace everything of any philosophy, just those parts that work for you.
Wolf Kahn

 

The art of losing isn't hard to master. So many things seem filled with the intent to be lost that their loss is no disaster. 
Elizabeth Bishop 1911-1979 (poet - Dichterin)

Painting is a language which cannot be replaced by another language. I don’t know what to say about what I paint, really.
Balthus

My painting is based on the fact that only what you can see is really there. (1968) Frank Stella

Why do two colors, put one next to the other, sing? Can one really explain this? No. Just as one can never learn how to paint.
Pablo Picasso

When I have a terrible need of.. shall I say the word.. religion.. I go out and paint the stars.
Vincent van Gogh

Life is hardly more than a fraction of a second. Such a little time to prepare oneself for eternity!
Paul Gauguin

Throughout the time in which I am working on a canvas I can feel how I am beginning to love it, with that love which is born of slow comprehension.
Joan Miro

Practice what you know, and it will help to make clear what now you do not know. Rembrandt

I am always doing that which I cannot do, in order that I may learn how to do it.
Picasso

Have no fear of perfection. You’ll never reach it.
Salvador Dali

To create one’s own world in any of the arts takes courage.
Georgia O’Keeffe

I try to apply colours like words that shape poems, like notes that shape music. 
Joan Miro

Art evokes the mystery without which the world would not exist.
René Magritte

Life obliges me to do something, so I paint.
René Magritte

The painting has a life of its own.
Jackson Pollock

The mind which plunges into surrealism, relives with burning excitement the best part of childhood.
Andre Breton

Figuring out our gifts in life is part of our journey to becoming enlightened human beings.
Allison Dubois

One must still have chaos in oneself to be able to give birth to a dancing star.
Friedrich Nietzsche

Without music, life would be a mistake.
Friedrich Nietzsche

It is necessary to work, if not from inclination, at least from despair. Everything considered, work is less boring than amusing oneself.
Charles Baudelaire

I am out to introduce a psychic shock into my painting, one that is always motivated by pictorial reasoning: that is to say a fourth dimension.
Marc Chagall

There is no must in art because art is free.
Vasilii Kandinsky

People who make art their business are mostly imposters, and have lured the wealthy to desire the peculiar, the eccentric and scandalous in today's art. I have fed these fellows what they wanted and satisfied the critics with all the ridiculous ideas that passed through my head. The less they understood, the more they admired me. (1945)
Pablo Picasso

What one does is what counts and not what one had the intention of doing.
Pablo Picasso

By amusing myself with all these games, all this nonsense, all these picture puzzles, I became famous... I am only a public entertainer who has understood his time.
Pablo Picasso

All things considered, there is only one Matisse.
Pablo Picasso
N.B. Picasso considered Matisse to be the father of modern art.
 

One never knows what one is going to do. One starts a painting and then it becomes something quite else. It is remarkable how little the 'willing' of the artist intervenes.
Pablo Picasso

When the individuality of the artist begins to express itself, what the artist gains in the way of liberty he loses in the way of order.
Pablo Picasso

The use of expressive colors is felt to be one of the basic elements of the modern mentality, an historical necessity, beyond choice.
Henri Matisse