The difference between the gradual approaches to samadhi and the practice of Chan is that Chan uses methods whereby one practices to realize wisdom directly, without the need to cultivate successive levels of samadhi. When enlightenment is realized in CHan, both samadhi and wisdom manifest together. Thus, while ordinary samadhi is a means for calming the mind and reducing vexations, it is not in itself wisdom (until one attains the highest samadhi, which is simultaneous with enlightenment).
In order for wisdom to manifest, one must leave behind the "one-mind" of samadhi for the "no-mind" of enlightenment. In no-mind, one has left behind the bliss of samadhi, in which there is still a trace of self-identity. In no-mind, at least temporarily, one has left behind all cognitive thinking, all attachment, and all discrimination. In Chan the idea is to cultivate methods of realizing no-mind directly. When realized, wisdom becomes the function of living one's life appropriately, spontaneously, and usefully without attachments or vexations. In this state one can be most effective in applying skillful means to help sentient beings.
Compassion and loving-kindness
A natural and spontaneous expression of wisdom is compassion, responding freely to the needs of sentient beings. Loving-kindness (maitri) and compassion (karuna) are cultivated at all levels of the bodhisattva path (see Lesson 6), but the highest expression of compassion occurs in equanimity (upeksha) where skillful means (upaya) are used to relieve suffering in others, without discrimination or self-reference. Equanimity being one of the seven factors of enlightenment, in the enlightened mind there is no discrimination between wisdom and compassion—they are "equal." Compassion at this level is just the manifestation of wisdom as perceived by sentient beings.
Ultimately, the practice of the three disciplines—precepts, concentration and wisdom—is common to all forms of authentic Buddhism, including Chan. Chan is not a shortcut whereby one can attain enlightenment by bypassing the precepts and samadhi.