不要說嘴 The Sabre Speaks For Itself
老魔道：「猴兒不要說嘴，看我這二刀來，決不容你性命。」行者道：「左右也只這般砍罷了。」老魔道：「猴兒，你不知這刀：老魔道：「猴儿不要说嘴，看我这二刀来，决不容你性命。」行者道：「左右也只这般砍罢了。」老魔道：「猴儿，你不知这刀：
逐句解 Line by line
The old fiend said, "Monkey, no more boasting. Watch this second cut come — I will not spare your life."
說嘴 is to talk big, to brag — vernacular and slightly contemptuous. The demon has just been told, in verse, why the first cut failed, and his response is to try the same thing again.
Wukong said, "Either way you will only chop like that again."
左右 here is a vernacular either way, in any case. 罷了 closes the sentence with a shrug: that is all there is to it.
The old fiend said, "Monkey, you do not know this sabre:"
The exact formula Wukong used on him two passages ago — you do not know — followed by a poem. The demon has decided that if his opponent answers a sword with a recitation, he will do the same.
Made in a furnace of gold and fire, wrought by divine craft through a hundred temperings.
Six lines of five and five, rhyming throughout on the 蕭豪 group — the -ao and -iao family. 中 is plain zhōng, inside. And note that his sabre and Wukong's skull were made the same way, in a furnace, over a long time.
This is where the fight turns into a recital competition, and the book is perfectly aware of the absurdity. Two enormously powerful creatures are standing outside a cave taking turns to perform poems about their equipment.
The demon's decision to answer in kind is the best thing about him. He could swing again. Instead he recognises the register his opponent is working in and matches it, in a tighter metre — five and five against Wukong's seven and seven — which is a small formal boast in itself.