Zazen and Behavior (Behavioral Changes in Practitioners)
For fifteen years I was a dervish in a traditional (Muslim) Sufi order in California. During this time I heard numerous talks by my own Sheikh and visiting Sheikhs on moral topics. Some of the moral issues addressed were sexual misconduct, theft from employers, angry behavior, and possessiveness or non-generosity.

I left the Sufi order for economic reasons and moved to Texas. Living in the greater Houston area, and wishing to continue spiritual practice, I could find no traditional Sufism, but in time I found the San Francisco Zen Center. Thereupon I immersed myself in Zen, attending practice periods at Tassajara and Green Gulch Farm, and becoming a member of the Houston Zen Center, a branch of the San Francisco Zen Center. In the time spent in these venues, I attended numerous talks by various Zen teachers. Curiously, in contrast to the Sufi setting, at no time over another fifteen years did I ever hear a Zen teacher discuss a moral issue with an assembled sangha. At present I am a member of a Zen Center in Hawaii, and the fact remains the same there; there have been no talks with the sangha about moral issues.
Not that there is any necessity for such talks, in my view. Zen of course has its “Grave Precepts” that provide an ethical foundation for practitioners. These precepts are to avoid killing, stealing, misusing sexuality, lying, getting intoxicated, gossiping about the faults of others, praising oneself compared to others, being possessive (non-generous), harboring ill-will, and disparaging the treasures of Buddha, Dharma, and Sangha. It may be enough for Zen Centers to arrange for students to be aware of these precepts, which in my experience they do. Zazen itself, in the normal case, will bring about desirable behavioral changes.
Zazen itself does cause remarkable positive changes in people. At intervals when I would return to Tassajara between practice periods, I could see these changes in students I had encountered there previously. I remember one woman in particular who evolved over months from being retired, sulky, and irritable to being outgoing and cheerful.
In talks published in 2007 in Shambhala: The Sacred Path of the Warrior, Chogyam Trungpa, the great Tibetan teacher, summarizes some of the positive changes brought about by meditation. Trungpa’s version of meditation is very close to zazen. The changes he speaks of include discovery of one’s Buddha nature or the inherent goodness of oneself; awakening of the heart, which leads to generous extension of oneself to others; ability to renounce ego for the sake of service to others; and a sense of being in command of oneself and of one’s world.
These interior changes occasioned by meditation no doubt lie behind the positive changes in behavior that I saw in students at Tassajara. Zazen can be relied upon to bring about such changes. However, zazen can obviously be used for reasons not approved by Buddhism, such as to improve one’s focus in order to be a better conman, hitman, whatever. Zazen will also not make for positive changes in a deeply flawed character that acts on exploitative impulses. In the October, 2019 edition of the journal, Lion’s Roar, the Buddhist teacher, Trudy Goodman, discusses the problem of sexual abuse of students by Buddhist teachers. There have been Zen teachers, obviously zazen practitioners, who have engaged in such abuses. Zazen has no power to change the behavior of a person who does not restrain himself from acting out corrupt urges.