雙輪日月 The Same Old Sun And Moon
你看那行者和三太子領了兵將，望洞裡只是一溜。駕起雲光，擡頭一望，果然好個洞啊：你看那行者和三太子领了兵将，望洞里只是一溜。驾起云光，抬头一望，果然好个洞啊：
逐句解 Line by line
Look at them: Pilgrim and the Third Prince took the troops and went down into the cave in one long slide.
一溜 is a slide, a single unbroken run — a whole army going down a jar-sized hole like water down a drain. 將 is jiàng, the generals of 兵將, and 太子 takes zǐ.
They raised their cloud light, lifted their heads and looked round — and it really was a fine cave:
The cue for verse, and what follows is a lyric rather than a battle poem. The novel stops an assault to describe the property.
The same old sun and moon, twin wheels; the same view of hills and streams.
依舊 is the same as before, and it is the strangest word in the poem. Underground, at the bottom of a bottomless cave, there are a sun and a moon and they are the ones you know. The cave is not a hole; it is a second world with its own sky.
Pearl pools and jade wells warm the mist.
珠淵玉井 is a matched pair of four characters, and 弢 is a rare one meaning to sheathe or wrap — the warmth wraps the mist rather than burning it off.
And there is much more worth envying.
更 is gèng, still more, not the gēng of a night watch. 堪羨 is worth envying, and the poem means it: a reader is being invited to want to live here.
The lyric is the last set-piece of the chapter and it is doing something unexpected. This is the demon's home, and the poem describes it as desirable — sun, moon, streams, warm pools, and a plain statement that there is more here worth having.
It matters for how the fiend is understood. She is not squatting in a pit. She built a world, and the army sliding down the drain is about to take it apart.