If you understand that zazen is the great gate of the law, you will be like the dragon piercing the water or the tiger re-entering the deep forest.Master Dogen XIIIth century
Some 'Zen-speak' is still a mystery to me - descriptions of satori experiences in terms of 'mountains walking' for example. But this excerpt does resonate with me.
What Dogen means is that Zazen practice is the way to achieve the awakening of the Buddha. The images of a dragon piercing the water and a tiger entering a forest are beautiful poetic metaphors to evoke, for me, the sense of 'organic' emersion of the state of samadhi (objectless absorption) of zazen. But this is not a new place. Zazen is not adding something new - it is stripping away the conventional illusions of discreet and dualistic existences to reveal bare reality - a reality which ultimately can't be prised apart into distinct parts or discreet essences and which is inseparable from ourselves. We are returning to our natural home. This is what is referred to as the 'original mind'. Hence, the tiger is 're-entering' the forest and the dragon is returning to the water (the natural home of dragons in oriental mythology).