A little further down in the same letter, #663 to Theo:
Myself, I only have the choice between being a good painter or a bad one. I choose the former. But the things needed for painting are like those of a ruinous mistress; you can do nothing without money, and you never have enough of it.
And so painting should be done at society’s expense, and the artist shouldn’t be overburdened by it.
But there you are, we should keep quiet once again, because nobody is forcing us to work, indifference towards painting being, inevitably, fairly general, fairly eternal.
Nobody is forcing us to do what we do. But the inevitability and beauty and wonder is clear to us. Keep on keeping on.