Zen Master Dogen instructed,
In the ocean, there is a place called the Dragon-Gate, where vast waves rise incessantly. Without fail, all fish once having passed through this place become dragons. Thus, the place is called the Dragon-Gate.
The vast waves there are not different from those in any other place, and the water is also ordinary salt water. Despite that, mysteriously enough, when fish cross that place, they all become dragons. Their scales do not change and their bodies stay the same; however, they suddenly become dragons.
The way of Zen monks is also like this. Although it is not a special place, if you enter a monastery, without fail you will become a buddha or a patriarch. You eat meals and wear clothes as usual; thus you stave off hunger and keep off the cold just the same as other people do. Still, if you shave your head, put on a kesa, and eat gruel for breakfast and rice for lunch, you will immediately become a Zen monk. Do not seek afar to become a buddha or a patriarch. Becoming one who either passes through the Dragon Gate or not depends only on entering a monastery, just the same as the fish.
There is a saying in the secular world, “I sell gold, but no one will buy it.” The Way of the buddhas and patriarchs is also like this. It is not that they begrudge the Way; even though it is always being offered, no one will accept it. To attain the Way does not depend on whether you are inherently sharp or dull witted. Each one of us can be aware of the dharma. Slowness or quickness in attaining the Way depends on whether you are diligent or indolent. The difference between being diligent or indolent is caused by whether your aspiration is resolute or not. Lack of firm aspiration is caused by being unaware of impermanence. Ultimately speaking, we die moment by moment, not residing for even a little while. While you are alive, do not spend your time in vain.
There is an old saying, “A mouse in a storehouse starves for food. An ox plowing the field never eats his fill of grass.” This means that even though living in the midst of food, the mouse is starving; even though living in the midst of grass, the ox is short of grass. Human beings are also like this. Even though we are in the midst of the Buddha-Way, we are not living in accordance with the Way. Unless we cut off the desire for fame and profit, we cannot live in peace and joy (nirvana) throughout our lifetime.