‘What is the most important thing in life? A lot of people would reply, “Money!” But money isn’t the most important thing for us. First of all it’s air; then, water, temperature, light, food, etc. Money is further down the list. Since our country is blessed with air and water, we Japanese completely forget the value of air and water. Moreover, this air and water must be pure, without odor or taste. They must be things in which there is nothing in particular. This “nothing in particular” is so natural, that we don’t realize that is is the most important thing in life.’  (The Zen Teaching of “Homeless” Kodo)

Although he does not say it in this paragraph, basically, he is talking about zazen.