Boqin could only call the servants and have the horses led along.

只得 again — 'could only', with 得 read dé — and again it marks a reluctant yes. Boqin does not want to make this climb either.

He then supported Sanzang and climbed once more up the high mountain; clutching vines and clinging to creepers, they made their way to the very summit,

攀籐附葛, clutching vines and clinging to creepers, tells you what kind of peak this is. Sanzang, who has no strength for it, has to be held up the whole way.

where indeed they saw ten thousand shafts of golden light and a thousand strands of auspicious vapour. There stood a great four-square boulder, and pasted upon it was a paper wrapper bearing six golden characters: 唵嘛呢叭𠺗吽.

The summit arrives wrapped in the standard signals of the sacred: ten thousand shafts of gold and a thousand strands of lucky vapour. The six characters pasted on the boulder are the great mantra 唵嘛呢叭𠺗吽, a sound-for-sound Chinese spelling of the Sanskrit Oṃ maṇi padme hūṃ, the six-syllable formula of Avalokiteśvara — Guanyin. The rare character 𠺗 exists here purely to carry a sound; the reading given, ǎn má ní bā mī hōng, follows the way the mantra is chanted in Mandarin.

Sanzang came forward and knelt; facing the characters upon the stone, he made several bows, and turning toward the west he prayed:

Before he dares touch it he kneels and bows several times. Whatever this seal is, everyone on the summit treats it as holy.

"Your disciple, Chen Xuanzang, has come by imperial command to seek the scriptures. If it is my destined lot to have a disciple, let me peel off these golden words, free the divine monkey, and together attain the Numinous Mountain. But if no such lot is mine — if this be some fierce and stubborn monster deceiving your disciple, unworthy of any blessing — then let the words not come away."

The prayer turns a rescue into a trial by omen. 陳玄奘 is the monk's own name, lay surname Chen with the monastic name Xuanzang. 徒弟之分 is the allotted lot of discipleship, with 分 read fèn, 'the share fate has assigned you' — that is what he is asking Heaven to confirm. 靈山, the Numinous Mountain (Gṛdhrakūṭa, Vulture Peak), is the Buddha's seat and the far end of the journey. And he sets the terms out plainly: if the words lift, this monkey is his fated disciple; if they hold, a fraud.

His prayer done, he bowed again; and when the bowing was finished, he stepped forward and gently peeled the six golden characters away.

It comes away at a touch, which is the answer. 將 is once more the marker for what the verb acts on, read jiāng.

At once a gust of fragrant wind arose, snatched the seal-strip from his hand, and swept it up into the air, while a voice cried: "I am the Guardian appointed to press down the Great Sage. Today his ordeal is fulfilled, and we return to see the Tathāgata and deliver back this seal."

The seal does not merely drop off. A scented wind snatches it out of his hand, and the guardian spirits who have been standing watch announce that they are returning it to the Buddha now the sentence has been served. 難滿 — the ordeal complete, 難 read nàn — formally closes Wukong's five hundred years.

So startled were Sanzang and Boqin and all their party that they bowed toward the empty sky.

嚇得, 'so startled that', with 得 read de. There is nothing to bow to any more, so they bow at the sky.

Then they went straight down the mountain and came again to the stone chest, where Sanzang said to the monkey, "The seal is peeled away — you may come out now."

Back down to the prison to let the prisoner out. Sanzang's announcement is as plain as it could be: the seal is gone, come out — and with that his part in the rescue is finished.

The monkey rejoiced and called, "Master, please stand off a little, so that I may come out without alarming you."

The courtesy is a lovely touch and a very funny one: after five hundred years he pauses on the threshold to ask the monk to stand back a bit, in case coming out should startle him. It does rather more than startle him.