The gate is a universal metaphor. In the Gospels, Jesus speaks of the narrow gate, and refers to himself as the gate. The Lotus Sutra speaks of the gate of knowledge as being difficult to enter. In the Koran, Muhammed describes himself as the city of knowledge and Allah as the gate. And Zen points to the “Gateless Gate.”
The ultimate gates are birth and death. Birth is literally a difficult passage for the “traveler” who would enter the world, and life is a search for easy gates to one temporal state or another, often distracted from the necessary end, which is to learn how to recognize the final gate.
The image of the gateless gate suggests that our anticipation, preparation and study may not get us to the expected gate. Events may change our minds, blind us to the road before us, mislead us down a fruitless path. The gate, like death, like life, is before us right now. We have but to enter it and abide in the place we have accessed, finding in the end that it is the same place from which we entered.