From Thomas Cleary’s The Zen Reader:
Worldly afflictions are as extensive as an ocean, noisy and clamorous; but they all arise from the thoughts in your own mind. When not a single thought is conceived, you are liberated from them all.
Since it depends on one’s own self, how hard could it be? Attaining Buddhahood shouldn’t even take a finger snap.
Viewed in this way, it seems very easy; but even so, you must be the one to do it. An ancient also said, “The moment you produce a thought, it is an object; just don’t have a single thought, and objects disappear, so mind dies out spontaneously, and there is nothing more to pursue.”
Those who already have good roots will understand this kind of talk the moment they hear it. Those who may be slower should look into it over and over — ultimately what principle is this?
– Ta-tu (17th Century)
Moving On Up a Little Higher 