I love Jane Kenyon (who died in 1995). She was the first poet I ever connected with. This quote is from a lecture she once gave titled “Everything I Know About Poetry.” I believe it’s found in a collection of her essays, A Hundred White Daffodils. (But don’t hold me to it.) If you like her, I wholeheartedly recommend her Collected Poems, even (especially!) if you’re new to poetry.