From which text is the quote by Buddha “My practice is the nonpractice, the attainment of nonattainment” taken? I was reading an article on Tricycle written by Thich Nhat Hanh, in which he quotes Buddha as follows:


  “My practice is the nonpractice, the attainment of nonattainment.”


From which text is this quote taken?
Here it says, its from the Sutra of 42 Chapters.