扶杖還禮 Leaning on His Staff He Bows
那老者扶杖還禮道：「長老那方來的？」唐僧合掌道：「貧僧東土唐朝差往雷音拜佛求經者。今至寶方，遙望城垣，不知是甚去處，特問老施主指教。」那老者扶杖还礼道：「长老那方来的？」唐僧合掌道：「贫僧东土唐朝差往雷音拜佛求经者。今至宝方，遥望城垣，不知是甚去处，特问老施主指教。」
逐句解 Line by line
The old man steadied himself on his staff, returned the greeting, and said, "Elder, from what quarter have you come?"
還 is huán here, to give back — returning a salute — and not the far commoner hái that means still or yet. The whole chapter turns on courtesies being returned properly, and this is the first of several. 那 is nǎ, the question word: from which direction. The old man is leaning on his stick to bow, which is a small, exact detail about age.
The Tang Monk pressed his palms together and said, "This poor monk was sent from the Tang court in the Eastern Land to Thunderclap, to bow before the Buddha and seek the scriptures.
Tripitaka's standard self-introduction, delivered perhaps thirty times in the novel and word-perfect every time. 差 is chāi here, to dispatch on official business — he was sent, by an emperor, with papers. The other reading of the character means to fall short or differ, and the base reading of most dictionaries lands there, which makes this one of the easiest words in the book to get wrong. 貧僧, this poor monk, is the humble self-reference every cleric uses.
Now I have reached your precious region, and seeing walls in the distance I do not know what place this is. I ask the old benefactor particularly to instruct me."
寶方, your precious region, is pure politeness — you inflate the other person's locality as a matter of form. 施主 is the word a monk uses for a lay donor, literally the giver-master, and applying it to a stranger met on a road is a courtesy rather than a description. 指教, to point and instruct, is the standard formula for asking a favour of information.
This exchange is almost entirely made of manners, and that is the point of including it. Two strangers meet on a road and spend four sentences establishing that each will treat the other as a superior.
Tripitaka's introduction is worth reading closely because it is the pilgrimage in one sentence: where he is from, who sent him, where he is going, and why. He has said it so often that it has worn smooth, and he will say it again to the prince within the hour.
The politeness is not merely decorative. The pilgrims are four very strange-looking travellers approaching a walled town, and the whole first half of this chapter is about whether they will be received as monsters or as monks. Tripitaka going first, on foot, with his palms together, is a strategy.