In Case 18 from the koan collection
Entangling Vines (translated by Thomas Kirchner), the teacher, Huitang Zuxin quotes a line from Confucius to his student, the poet Shangu: "My friends, do you think I'm hiding things from you? In fact, I am hiding nothing from you." And then he says, "It's just the same with the Great Matter of Zen. Do you understand this?" Shangu doesn't understand, but later, while walking in the mountains with his teacher, the air is full of the scent of sweet-olive blossoms, and Huitang asks, "Do you smell the fragrance of the blossoms?" When Shangu says that he does smell them, Huitang says, "You see, I'm hiding nothing from you." And Shangu has an awakening.
When I was new to Zen, I came to my first teacher for an individual meeting,
dokusan, full of distress about something or other. I have no memory at this point what I was bothered about, but my teacher choose to ignore all of that anyway, and asked me, "Do you hear the call of the mourning dove outside?" That beautiful call, which sounds like someone singing, "who, who, who" had been out of my awareness until my teacher called attention to it. And in that moment, as my ears turned to that lovely sound, there was nothing else in the universe. Just for a moment. But after all these years, that moment is evoked every time I hear doves calling. Everything is like this. Our practice is to stop and see, listen, smell, taste, touch whatever is right here with us. This is the Great Matter of Zen. You see, I am hiding nothing from you.