樂以忘憂 Taking Joy, He Forgets His Cares
行者聞說，笑呵呵道：「師要身閑，有何難事？若功成之後，萬緣都罷，諸法皆空。那時節，自然而然，卻不是身閑也？」長老聞言，只得樂以忘憂。放轡催銀濁，兜韁趲玉龍。行者闻说，笑呵呵道：「师要身闲，有何难事？若功成之后，万缘都罢，诸法皆空。那时节，自然而然，却不是身闲也？」长老闻言，只得乐以忘忧。放辔催银浊，兜缰趱玉龙。
逐句解 Line by line
When Pilgrim heard this he laughed aloud and said: "If the Master wants his body at rest, where is the difficulty in that?
Pilgrim, who has been waiting for this, gives the Chan answer. 笑呵呵, xiào hē hē, "with a great laugh"; 身閑 picks up the Elder's own last two characters and hands them back.
Once the work is achieved, the ten-thousand ties all cease, and the dharmas are one and all empty.
萬緣都罷, wàn yuán dōu bà, "the ten thousand attachments all fall away" — 緣 is the pull that binds a person to the world, and 都 is dōu. 諸法皆空, "all things are empty," is Buddhism's bluntest formula, the same emptiness the Heart Sūtra was arguing two passages back.
At that time, of itself and so of itself, will the body not then be at rest?"
自然而然, zì rán ér rán, "of itself, and so of itself" — the phrase where the modern word for "nature," 自然, comes from. In 那時節, 那 is nà. Pilgrim's point: rest is not a thing you take, it is a thing that arrives once you have stopped grabbing.
Hearing these words, the Elder could do no more than take such joy as forgets all care.
The master gives in. 只得, zhǐ dé, "had no choice but to" — 得 here dé, 長 zhǎng. 樂以忘憂, lè yǐ wàng yōu, "so glad he forgets his worries," is Confucius describing himself in the Analects — and the novel is about to hang it on somebody else entirely. Hold that thought.
Loosing the reins, he urged on the silver steed; gathering the halter, he hastened the jade dragon.
A two-line couplet sends them on their way: loose the reins on one mount, gather the halter on the other. 放轡, fàng pèi, against 兜韁, dōu jiāng. The oddity is 銀濁, yín zhuó: paired against 玉龍, "jade dragon," it clearly stands for the horse, but 濁 means "muddy," which is no compliment to a mount. Other editions print a character for a bright mane here. The 世德堂本 prints 濁, so 濁 is what stands, read zhuó.
Pilgrim's reply is a small piece of Chan argument. You want rest? Then finish the work: once the ten thousand attachments drop and all things are seen to be empty (萬緣都罷，諸法皆空), ease turns up 自然而然, of itself. He is not offering a holiday. He is saying that rest is a by-product of waking up, and cannot be had any other way. Once again the disciple teaches the master, and the master can only 樂以忘憂, be glad and forget his worries.
Watch that phrase. It is Confucius's self-description in the Analects, and within two passages the novel will pin it to the coat of a woodcutter on a mountainside — who is not a woodcutter. The passage ends on a five-and-five couplet of departure: reins loosed on the silver mount, halter gathered on the jade dragon. The 世德堂本 prints 濁, "muddy," where the parallel with 玉龍 wants something bright and maned. The edition's reading stands and is glossed rather than quietly improved; where this text and other printings disagree, this text wins.