Reading through Kōshō Uchiyama Roshi's “Opening the Hand of Thought”:
“To truly repent does not mean offering an apology; rather, repenting requires facing life straight on, and letting the light of absolute reality illuminate us. What does it mean to be illuminated by absolute reality? The Samantabhadra Bodhisattva Dhyana Sutra says, “If you want to repent, sit zazen and contemplate the true nature of all things.” In other words, it is in doing zazen that true repentance is actualized.
We who practice zazen hold this vow, and function with it as our life direction, while at the same time we just keep returning to zazen repenting at being unable to carry out that vow. This is what constitutes the religious life of the Buddhist practitioner: living by vow and repentance, and being watched over, protected, and given strength by zazen. Where there is no vow, we lose sight of progress; where there is no repentance, we lose the way. Vow gives us courage; repentance crushes our arrogance. This is the posture of a vivid, alive religious life.”