"Why did you not protect my master unseen? Where had you all gone?"

The accusation, and it is fair. The Sentinels' job is precisely to guard this pilgrimage 暗中, out of sight. A reading: 那 is nǎ, the interrogative — where had you gone — not the nà of pointing.

The Sentinel said, "Your master let his Chan nature go slack, took his pleasure at the Monastery of Compassionate Clouds in Jinping Prefecture, and so, Peace reaching its height turned to Obstruction, and joy at its fullest became grief; and now he has been seized by fiends.

The chapter's own diagnosis, delivered by a civil servant. 寬了禪性 — he loosened his Chan nature — is exactly the charge the opening lyric laid before any of this happened. And 泰極生否 is a technical phrase: 泰 and 否 are hexagrams 11 and 12 of the Book of Changes, Peace and Obstruction, and they sit next to each other because one turns into the other. The everyday version, 否極泰來, runs the other way and is still said to console people. Here it is reversed, and it is not consoling. A reading: 否 is pǐ, the hexagram — chapter 1 seals it at 萬物否矣 — and not the everyday fǒu meaning "not."

"He has the guardian monastery-spirits about him, keeping him safe.

伽藍 is a Chinese rendering of the Sanskrit saṃghārāma, a monastery — and by extension the tutelary spirits who guard one. They have travelled with Tripitaka since the start of the journey, which is why the news is bad but not yet fatal.

"We knew the Great Sage had been searching all night, and feared he might not know these hills, so we came on purpose to bring word."

The reason for the visit, and it is administrative rather than heroic: they have come to deliver information to a colleague working out of area.

Pilgrim said, "If you came to bring word, why hide your names and change your shapes, driving three sheep along and hollering away like that?"

Fair question, briskly put. Note the second 喝: 吆吆喝喝 doubles both halves of the word for hollering, and both of those graphs read hè, to shout, not hē, to drink. And 作甚 takes 甚 as shèn even standing alone as an interrogative, which is what the sealed corpus does at 有甚禍事.

The Sentinel said, "We set out these three sheep to answer the word Kāitài — it is called 'Three Yang Open into Peace' — so as to break the Obstruction that binds your master."

And here is the pun, spelled out. 三陽開泰 is a New Year greeting every Ming reader knew from doorways and paper cuttings: the Three Yang open into Peace, meaning hexagram 泰 whose three lower lines are unbroken yang, which is why spring returns. The joke is that 陽, yang, and 羊, sheep, are homophones — so the greeting is traditionally drawn as three sheep. Heaven's messengers have dressed themselves as a piece of festival decoration, and they have done it as a working countermeasure: the picture of 泰 set against the 否 the Sentinel has just diagnosed. Two readings: 應 is yìng, to answer or correspond to, and 塞 in 否塞 is sè, obstruction — the corpus seals the same reading at 阻塞門路.

Pilgrim was angry enough to strike them, but seeing that this was their meaning, he let them off, put away his cudgel, and turning his temper to good humour said, "Is this mountain the demons' place, then?"

回嗔作喜 — turning anger into pleasure — is a set four-graph phrase for a mood switching in one movement, and it is Pilgrim's characteristic one. He was going to hit them a moment ago. He works out what they meant, and the cudgel goes away.