So it is unlike what is taught in Chan, i.e. the sudden teaching (dunjiao 頓教).
'In a single leap, you directly enter the stage of Tathāgata.
Just grasp the roots, don’t worry about the branches;
It is like a pure beryl gem containing the moon.
Having understood this wish-fulfilling gem,
Using it for the benefit of yourself and others, it will never be exhausted.'
(Yongjia’s Song of Actualizing the Way, BDK ed, p 14)
'To simply right now suddenly comprehend that one’s own mind is fundamentally Buddha, without there being a single dharma one can attain and without there being a single practice one can cultivate—this is the insurpassable enlightenment, this is the Buddha of suchness.'
(Essentials of the Transmission of Mind, in Zen Texts, BDK ed, p 20)
It is discussed in the Chapter on Practice in the Anguttara Nikaya (4.161-170). There it becomes clear that 'easy' stands for the four absorptions, and 'quick' for the five powers being strong. It is still a gradual path.Four Courses of Meditation (pratipad); one of the four courses is quick and easy.