善惡之報 Good and Evil
行者禁不得疼痛，跪於路傍，只叫：「莫念，莫念，有話快說了罷。」唐僧道：「猴頭，還有甚說話？出家人行善，如春園之草，不見其長，日有所增；行惡之人，如磨刀之石，不見其損，日有所虧。你在這荒郊野外，一連打死三人，還是無人檢舉，沒有對頭；倘到城市之中，人煙湊集之所，你拿了那哭喪棒，一時不知好歹，亂打起人來，撞出大禍，教我怎的脫身？你回去罷。」行者禁不得疼痛，跪于路傍，只叫：「莫念，莫念，有话快说了罢。」唐僧道：「猴头，还有甚说话？出家人行善，如春园之草，不见其长，日有所增；行恶之人，如磨刀之石，不见其损，日有所亏。你在这荒郊野外，一连打死三人，还是无人检举，没有对头；倘到城市之中，人烟凑集之所，你拿了那哭丧棒，一时不知好歹，乱打起人来，撞出大祸，教我怎的脱身？你回去罢。」
逐句解 Line by line
Pilgrim, unable to bear the pain, knelt in the road and only cried: "Stop, stop! If you have something to say, say it quick, and be done."
禁不得疼痛 (jīn bù de téng tòng) "could not endure the pain," the complement 得 (de). 跪於路傍 (guì yú lù páng) "knelt by the road." Wukong, kneeling under the fillet's agony a second time, once more begs a hearing — the pattern of the earlier spell-scene painfully repeated.
The Tang Monk said, "Monkey-head, what more have you to say?
猴頭 (hóu tóu) "monkey-head." 還有甚說話 (hái yǒu shén shuō huà) "what more have you to say," 還 (hái), 甚 (shén). The elder's cold question prefaces not a hearing but a lecture — his mind is already made up.
"A monk who does good is like the grass of a spring garden: you do not see it grow, yet day by day it increases.
行善 (xíng shàn) "to do good," 行 (xíng). 不見其長，日有所增 "you do not see it grow, [yet] daily it adds" — here 長 (zhǎng) "to grow." The famous simile likens goodness to spring grass, its increase imperceptible but constant.
"A person who does evil is like a whetstone for a knife: you do not see it wear, yet day by day it wastes away."
行惡 (xíng è) "to do evil," 行 (xíng). 磨刀之石 (mó dāo zhī shí) "a knife-whetting stone"; 不見其損，日有所虧 "you do not see it wear, [yet] daily it diminishes." The paired simile — evil like a whetstone, wasting unseen — completes the elder's homily on the hidden accumulation of good and ill.
"Out here in this wild waste, you've beaten three people to death in a row, and still there's no one to report it, no plaintiff against you;
荒郊野外 (huāng jiāo yě wài) "desolate wilds." 還是無人檢舉 (hái shì wú rén jiǎn jǔ) "still no one to lay information," 還 (hái); 對頭 (duì tóu) "an adversary, accuser." The elder's argument turns practical and worldly — here in the wilds the killings go unpunished, but elsewhere they would not.
"but should we come to a city, a place thick with people and hearth-smoke, and you take up that mourner's-club of yours and, in a fit of not knowing good from ill, fall to beating people at random and stir up some great calamity — how am I to get myself clear?
那哭喪棒 (nà kū sāng bàng) "that mourner's-staff" (a scornful name for the cudgel), 那 (nà). 人煙湊集 (rén yān còu jí) "crowded with people." 不知好歹 (bù zhī hǎo dǎi) "not knowing good from bad." 中 (zhōng) (城市之中); 教 (jiào) (教我). The elder foresees Wukong's violence unleashed in a city — a worldly, self-protective fear layered over the moral rebuke.
"Go back where you came from."
你回去罷 (nǐ huí qù bà) "go back, then" — the third dismissal, echoing the first two word for word. The repetition marks the deepening groove of the quarrel, each expulsion harder to reverse than the last.
Tripitaka's response to the exposed demon is not gratitude but a lecture, and the lecture is one of the chapter's most quoted passages: goodness is like spring grass, growing unseen but ever increasing; evil is like a whetstone, wearing unseen but ever wasting. It is genuine Buddhist moral teaching, beautifully phrased — and, aimed at the disciple who has just destroyed a fiend to save him, catastrophically misapplied.
Beneath the homily runs a more worldly anxiety. The elder frets that here in the wilds the "killings" go unpunished, but in a crowded city Wukong's cudgel might bring calamity down on them all — 教我怎的脫身, "how am I to get clear?" It is a strikingly self-protective note, mingling moral reproach with practical fear, and it shows the dismissal is driven as much by the elder's own dread as by principle.
The third 你回去罷, "go back where you came from," repeats the first two verbatim, and the repetition is the point: the pattern has hardened past the reach of plea or evidence. Where the earlier dismissals were reversed by Wukong's kneeling appeals, this one comes after the truth has been shown and rejected — and so it will not be undone, but will drive on to the dismissal letter and the final parting.