怪來自何方 Where Is That Fiend From
國王下殿親迎，口稱：「法師老佛。」師徒們將馬拴住，都上殿來相見。行者道：「陛下可知那怪來自何方？等老孫去與你一併擒來，剪除後患。」国王下殿亲迎，口称：「法师老佛。」师徒们将马拴住，都上殿来相见。行者道：「陛下可知那怪来自何方？等老孙去与你一并擒来，剪除后患。」
逐句解 Line by line
The king came down from the hall to welcome him in person, calling him "Master of the Law, Old Buddha."
老佛, Old Buddha, is flattery of the highest order and theologically nonsense — a monk is not a buddha. The king is a man who three hours ago wanted this person's heart in a cup, and his instinct is to overcorrect.
The master and his disciples tied up the horse and all went up into the hall to be received.
Even here somebody has to see to the horse. The novel is consistent about this: the white dragon horse is tied, fed and led on every single leg of the journey, and the detail is never dropped for the sake of a grand scene.
Pilgrim said, "Does Your Majesty happen to know where that fiend came from?
Straight to business, before anyone can start a ceremony. 可知 is a polite interrogative opener, closer to "would you happen to know" than a blunt "do you know."
Let old Sun go and seize him along with the other one, and cut off the trouble at the root."
剪除後患 — cut away future trouble — is the first of three times this phrase or its cousin appears in the next few passages. It is the language of statecraft, not of monks, and Wukong uses it because he is talking to a king. 一併 means taking both the Royal Father-in-Law and the queen together; he has worked out by now that they left as a pair.
The chapter changes gear here. Everything up to this point has been undoing a deception; from now on it is a hunt, and Wukong sets the terms before anyone offers him anything.
His phrase for it is worth noticing. He does not say he will punish the demon or rescue the queen; he says he will cut off future trouble. That is a promise about the kingdom's safety rather than about justice, and it is the promise a ruler actually wants.