曹洞宗的「修證一如」是指一切眾生本來是佛，並不是經過修行的過程才使眾生變成佛，因此修行應是以無求無得的正見去直觀本自具足的清淨佛性。如果以為努力修行將來可以成佛，那就是把佛當作追求的對象，落入能所對立的妄見和時間的幻覺當中，永無成佛之期。曹洞宗便是在這樣的佛理脈絡下講「只管打坐」和「默照」，以開放的心靈如實觀照身心內外的一切，不生任何執著和知見分別，方能回歸本來清淨的覺性。有別於一般的解釋，本文詳細論證《金剛經》的「若心有住即為非住」與「此心本來無住」或「眾生本來是佛」之意相同，而這是曹洞宗無為法修行的佛理根據。本文依據禪理重新詮釋「磨磚作鏡」的禪宗公案：懷讓禪師的磨磚並不是如很多人所誤會的，說是要告誡馬祖道一打坐不能成佛，而是提醒修行者不可以凡夫眾生自居而期盼將來能成佛，因為眾生當下即是佛，若作分別想，即迷失祖師本意矣。

“Unity of practice and enlightenment” as put forth by the Cao Dong (Soto) Zen Sect means that all sentient beings are intrinsically Buddha, rather than become Buddha through practice, and thus Zen practice should aim at intuitively seeing the primordial pure Buddha nature with a skillful mindset of no-craving. To think that an ordinary being can become Buddha through diligent practice is to falsely discriminate between the two and to regard Buddha as an object to be grasped, thus falling into the delusion of subjectobject opposition and of time as a substantial entity. Enlightenment can never be attained in this way. It is in this context of Buddhist insights that the Cao Dong Sect teaches “pure meditation” and “silent illumination,” which aim to observe all phenomena with mindfulness and openness as they really are, without any attachments and conceptual discrimination, so as to be awakened to the originally pure self-nature. This article reinterprets at length the clause in Diamond Sutra that “if the mind has abiding, it is no abiding,” arguing that it means the same as “the mind’s original nature is no-abiding,” or “all beings are originally Buddha.” This is the doctrinal foundation of the wu-wei (no-doing) practice advocated by the Cao Dong Sect. This article also reinterprets the Zen koan of “grinding a brick into a mirror,” pointing out that Zen master Huai-rang’s act of grinding a brick did not mean to warn his student Mazu that meditation can never lead to enlightenment, as many in the Buddhist communities have misunderstood, but to exhort him not to think of himself as an ordinary being who can become Buddha in the future. Because one is already Buddha from the transcendent perspective of the timeless “here and now,” and to discriminate between an ordinary being and Buddha is to miss the authentic teachings of Zen patriarchs.