快取刀來 Fetch A Knife Then
假唐僧道:「既如此,快取刀來,剖開胸腹,若有黑心,謹當奉命。」那昏君歡喜相謝,即著當駕官取一把牛耳短刀,遞與假僧。假唐僧道:「既如此,快取刀来,剖开胸腹,若有黑心,谨当奉命。」那昏君欢喜相谢,即着当驾官取一把牛耳短刀,递与假僧。
逐句解 Line by line
The false Tang Monk said, "In that case, fetch a knife quickly and cut open my breast and belly. If there is a black heart there, I shall respectfully obey the command."
謹當奉命 is the flattest court formula for compliance — the sort of thing a minister says when accepting a posting. 當 is dāng, the modal "shall." Wukong is agreeing to be disembowelled in the tone of a man accepting a committee assignment, and the mismatch is the point.
The muddled king, delighted, thanked him, and at once directed the officer of the guard to fetch an ox-ear dagger, which he handed to the false monk.
著 is zhuó here — the dispatching sense, "to set someone to do a thing" — not the zhe that marks an action in progress. A 牛耳短刀, ox-ear dagger, is a short curved blade named for its shape. The name has a grim history behind it: at an oath-taking the presiding lord cut off an ox's ear and the parties smeared their lips with the blood, which is why 執牛耳, "to hold the ox's ear," still means to be the leading figure in a field.
Wukong's acceptance is what tips the scene from horror into farce. He does not argue, plead or reveal himself. He asks for a knife. The king is 歡喜 — delighted — which tells you everything about how far gone he is.
The detail of the ox-ear dagger is doing quiet work. It is the blade of covenants and oaths, handed over here for a killing that breaks every covenant a king owes his monks and his subjects. The novel rarely explains such resonances; it puts the object in the scene and moves on.