磨刀水 The Water Off The Whetstone
行者笑道：「老官兒，你估不出人來。我小自小，結實，都是『吃了磨刀水的秀氣在內』哩。」眾老見說，只得依從道：「長老，拿住妖精，你要多少謝禮？」行者道：「何必說要甚麼謝禮？俗語云：『說金子晃眼，說銀子傻白，說銅錢腥氣。』我等乃積德的和尚，決不要錢。」行者笑道：「老官儿，你估不出人来。我小自小，结实，都是『吃了磨刀水的秀气在内』哩。」众老见说，只得依从道：「长老，拿住妖精，你要多少谢礼？」行者道：「何必说要甚么谢礼？俗语云：『说金子晃眼，说银子傻白，说铜钱腥气。』我等乃积德的和尚，决不要钱。」
逐句解 Line by line
Pilgrim laughed and said, "Old sirs, you cannot appraise a man.
估 is to value or price something. The commercial vocabulary again, and this time he is applying it to himself.
"Small I may be and small I am, but I am solid: it is the case of one who has drunk the water off the whetstone — the keenness is all inside."
The saying turns on a nice piece of folk physics: water that has run off a whetstone has carried the blade's edge away with it, so anyone who drinks it takes the sharpness inward. What looks slight is keen inside. 秀氣 is that fineness or keenness of quality.
Seeing how he spoke, the elders could only fall in with it. "Elder, once you have taken the demon, what thanks will you want?"
They give in, and the grammar shows it. 只得 is the "nothing-else-for-it" construction — 得 as the full verb dé, "to get," rather than the light particle it so often is in this chapter. They could only fall in with him.
Pilgrim said, "Why speak of wanting any thanks at all?
甚 is the question-word shén.
"The common saying has it: 'speak of gold and it dazzles the eye, speak of silver and it is a witless white, speak of copper cash and it stinks.'
Three parallel clauses of five characters, one per metal, each ending in a sensory objection — the glare of gold, the blank white of silver, the smell of copper.
"We are monks who lay up merit. We will take no money whatever."
積德, "laying up merit," is the Buddhist idea of a moral balance accumulating across lifetimes, and it is set here against the three kinds of coin he has just turned down.
The whetstone proverb answers the elders in the same currency the physiognomy tag used on the old man: received wisdom, quoted rather than argued, converting a visible defect into a hidden merit. That is twice now, on two different audiences.
The refusal of payment is also put as a proverb, and it is a strange one. Gold dazzles, silver is a stupid white, copper smells — three objections about how money strikes the eye and the nose, and not one about the ethics of taking it. The moral claim, 積德的和尚, only arrives afterwards.
He has spent the entire evening treating this as a transaction — a deposit, a contract, an appraisal — and now he declines the fee. What he actually wants has still not been said, and the elders have to ask again.