只有天在上 Only Heaven Stands Above
師徒們也自尋芳踏翠，緩隨馬步。正行之間，忽見一座高山，遠望著與天相接。三藏揚鞭指道：「悟空，那座山也不知有多少高，可便似接著青天，透沖碧漢。」行者道：「古詩不云：『只有天在上，更無山與齊。』但言山之極高，無可與他比並，豈有接天之理？」师徒们也自寻芳踏翠，缓随马步。正行之间，忽见一座高山，远望着与天相接。三藏扬鞭指道：「悟空，那座山也不知有多少高，可便似接着青天，透冲碧汉。」行者道：「古诗不云：『只有天在上，更无山与齐。』但言山之极高，无可与他比并，岂有接天之理？」
逐句解 Line by line
Master and disciples went looking for the fragrance and treading the green, following the horse's pace at their leisure.
尋芳踏翠, hunting the fragrance and treading the green, is a set phrase for a spring day out, and it is faintly comic applied to a pilgrimage under orders. 緩隨馬步 puts the men behind the horse rather than driving it along — the last relaxed image anyone gets in this chapter.
As they went, a high mountain suddenly came into view; from far off it looked joined to the sky.
A mountain appears, and it looks joined to the sky. 著 here is the little toneless zhe, hung on 望: looking, in the act of it, not the zhuó of putting something on. The character turns up twenty-nine times in this chapter and its reading is settled separately at every one.
Tripitaka raised his whip and pointed. "Wukong, there is no telling how high that mountain is. It looks as though it touches the blue sky and drives right up through the sapphire river."
Tripitaka's second clause goes one better than his first: not merely up to the sky but through it. 碧漢 is the Milky Way, the river of heaven. The whole argument that follows grows out of this one loose piece of hyperbole, which is worth remembering the next time he says a thing looks like something else.
Pilgrim said, "Does the old poem not say: Only heaven stands above it, and no mountain is level with it?"
Pilgrim answers hyperbole by citing a poem. The nested quotation takes the second pair of brackets, 『』, which this chapter keeps for a quotation inside a quotation and uses three times in all — and he will reach for the device again four units later.
"That only says the mountain is extremely high, with nothing to set beside it. How could there be any question of its touching the sky?"
And here is the point he is making. 比並 is the vernacular for setting two things side by side to measure them, so his objection is about measurement: the poem asserts a comparison, not a contact. He is reading a text closely — which is exactly what this chapter is about to ask of everybody, and exactly what nobody else manages.
The first real conversation of the chapter is an argument about how to read. Tripitaka sees a mountain that looks as though it touches the sky and says so; Pilgrim produces a couplet saying the same thing and then explains that it does not mean it.
That matters more than it looks. A few hundred characters from here the party will come on a building the text calls 也似雷音, a Thunderclap lookalike, and Tripitaka will insist on going in on the strength of the resemblance while Pilgrim urges caution. The mountain argument is the same quarrel rehearsed with nothing at stake — and Tripitaka loses this one.