Synopsis:
Master Hsuan Hua gave a teaching that is profound. See video below.
Reciting Amitabha's name is practicing Zen.
One who knows how to recite Amitabha's name knows how to practice Zen.
One who truly knows how to practice Zen will know how to recite Amitabha's name.
In fact, those who recite Amitabha's name are Buddhas. But, those who practice Zen are not necessarily Buddha.
When one recites "Namo Amitabha", there is Buddha in one's heart/mind. When that continues, one becomes Buddha. Due to the vow of Buddha Amitabha, the recitation of "Namo Amitabha" allows one to be transferred to the Pureland at the time of death. Then Buddhahood is the result.
For those who practice Zen only, the practice is a search for Buddha, which is different from reciting "Namo Amitabha" which is a direct access to the Buddha.
Committing seven days retreat practice of reciting "Namo Amitabha" keeps the practice strong. And is very good.