Saddhā: Trust
The confidence that opens the door. We which have believed do enter, so the entering turns on trust and not on one more heave of effort. Belief is the key that was in the hand all along. A traveler who simply believes the gate is open and walks through it.
Passaddhi: Calm
The settling of a mind that has stopped straining. Rest here means the churn going still, the way muddy water clears once you quit stirring it. Enter into rest names arriving where the thrashing ends. A shaken glass set down until it turns clear.
Asaṅkhata: The unconditioned
That which is not built and cannot break. The works were finished from the foundation of the world, so the rest was already complete before any striving began, waiting rather than made. Nothing you construct could add to it. A house standing ready before you ever picked up a tool.
Nibbāna: The cool peace
The great rest where the fires go out. My rest, sworn and held open, points past all labor to a stillness the works themselves cannot reach. To enter is to lay the burden down where it need never be shouldered again. A coal that stops glowing and finally cools in the palm.