You must experience the highest Dharma in order to reach Buddhahood. The sudden enlightenment Dharma is experienced by all Tathagatas and is shared by all the Tathagatas in the ten directions. It does not require that one spend three great kalpas reaching Buddhahood. The moment one attains sudden enlightenment, one is exactly the same as the Buddha. The Dharma experienced by the Buddha is exactly the same as the Dharma one experiences at the moment of one's enlightenment.

When a practitioner of gradual enlightenment reaches the first bhumi position of Bodhisattvahood, he experiences the Dharma that a Bodhisattva on the first bhumi level experiences. He has no idea what Buddhahood is like. If he reaches the arhat position of the Hinayana tradition, then he experiences what an arhat experiences, not what a Buddha experiences. But when one reaches enlightenment through sudden teachings, what one experiences is the same as Buddhahood. At most, great practitioners of outer paths may attain an illusory "no mind" state and the enlightenment of an arhat is a "no mind" state of emptiness. The enlightenment attained through sudden teachings, however, is a "no mind" state that is neither empty nor existent.

Do not misunderstand me. After you become enlightened, it does not mean you become a Buddha. When you attain enlightenment, what you experience is exactly the same as Buddhahood, but you are not a Buddha yet. The wisdom you acquire through the experience is the wisdom of Buddha, but your actions are still the actions of an ordinary sentient being. After you have an enlightenment experience, you must practice even more diligently in order to protect and nurture your holy embryo; it is a Buddha embryo, not a mature Buddha. Usually, after an enlightenment experience, you will have no difficulty practicing with determination, because your faith will deepen. But you are still an ordinary person. If you do not continue to practice, the experience and wisdom will regress and fade. You have to reinforce the practice by experiencing enlightenment again and again.