現相掣棒 Pilgrim Shows His True Form
行者在格子眼聽著兩個言語相攀，恐怕師父亂了真性，忍不住，現了本相，掣鐵棒喝道：「孽畜無禮！」那女怪見了，口噴一道煙光，把花亭子罩住，教：「小的們，收了御弟。」他卻拿一柄三股鋼叉，跳出亭門，罵道：「潑猴憊懶！怎麼敢私入吾家，偷窺我容貌？不要走，吃老娘一叉。」這大聖使鐵棒架住，且戰且退，二人打出洞外。那八戒、沙僧正在石屏前等候，忽見他兩人爭持，慌得八戒將白馬牽過道：「沙僧，你只管看守行李、馬匹，等老豬去幫打幫打。」好獃子，雙手舉鈀，趕上前叫道：「師兄靠後，讓我打這潑賤。」行者在格子眼听着两个言语相攀，恐怕师父乱了真性，忍不住，现了本相，掣铁棒喝道：「孽畜无礼！」那女怪见了，口喷一道烟光，把花亭子罩住，教：「小的们，收了御弟。」他却拿一柄三股钢叉，跳出亭门，骂道：「泼猴惫懒！怎么敢私入吾家，偷窥我容貌？不要走，吃老娘一叉。」这大圣使铁棒架住，且战且退，二人打出洞外。那八戒、沙僧正在石屏前等候，忽见他两人争持，慌得八戒将白马牵过道：「沙僧，你只管看守行李、马匹，等老猪去帮打帮打。」好呆子，双手举钯，赶上前叫道：「师兄靠后，让我打这泼贱。」
逐句解 Line by line
From the lattice-hole Pilgrim listened to the two of them drawing each other out in talk, and fearing that his master's true nature might be thrown into disorder he could bear it no longer: he resumed his own form, whipped out his iron rod and shouted, “Sinful beast, you forget yourself!”
Pilgrim breaks cover not because his master is in danger of being eaten but because he is in danger of being talked round: the phrase is 亂了真性, his true nature thrown into disorder. The two appearances of 相 differ — 相攀 is the mutual xiāng, drawing each other out; 本相 is xiàng, outward shape. 喝 is hè, to shout, not the hē of drinking. 畜 in 孽畜 is chù. And 真性 is the term the chapter title picks up when it promises that a rectified nature keeps the body unmarred.
When the woman fiend saw him she spat a shaft of smoky light from her mouth, throwing a cover over the flower pavilion, and gave the order: “Little ones, take the royal brother away.”
教 is jiào, to give an order. Her first act on being discovered is not to attack but to get her guest out of sight — 罩住 is to hood or cover something over. Remember that when the fight starts.
Then she took up a three-pronged steel trident, sprang out at the pavilion door, and railed at him: “Insolent, good-for-nothing ape! How dare you steal into my house and spy upon my face?
憊懶 is vernacular abuse: shiftless, good-for-nothing. 吾 is the bookish word for "I", a shade stiffer than the 我 she uses elsewhere — she is drawing herself up.
“Don't run off — take a taste of your old mother's trident!”
老娘 — "your old mother" — is a woman's swaggering self-designation in a quarrel, roughly the register of "yours truly" spat through the teeth.
The Great Sage brought up his iron rod to parry, fighting and giving ground by turns, and the two of them fought their way clear of the cave.
且戰且退 is the fixed formula for a fighting withdrawal: giving ground without turning your back.
Bajie and Sha Monk were waiting before the stone screen when of a sudden they saw the two of them at grips. In his alarm Bajie led the white horse across and said, “Sha Monk, you just mind the baggage and the horse, and let old Hog go and lend a hand at the fighting.”
看守 takes 看 as kān, to keep watch over — a different reading from the kàn of 看經 and 看打, and the only kān in the chapter. 慌得 is the "so alarmed that" construction and takes the particle de, agreeing with the same phrase in the opening passage. 幫 is always bāng, and 幫打幫打 doubles the verb to make it offhand: "lend a bit of a hand".
Splendid idiot! He raised his rake in both hands, ran forward and cried, “Stand back, elder brother, and let me strike this vile wench.”
好獃子 is the storyteller's cry of admiration, not a description — closer to "Now watch this!" than to any judgement on his intelligence. 獃子 takes the light zi. 潑賤 is coarse abuse aimed at a woman.
Pilgrim states his reason for breaking cover, and it is not rescue. He is afraid his master's 真性, his true nature, may be thrown into disorder — not that he may be eaten, or held, or hurt. The danger this chapter recognises is internal, and the term is the one the chapter title takes up when it promises that a nature kept straight will leave the body unmarred. Pilgrim intervenes at the exact moment when talk starts turning into persuasion.
Watch the order of the demon's response. She does not attack first. She spits a screen of smoky light over the pavilion, orders her servants to take the royal brother away, and only then picks up her trident and comes out. Her domestic arrangements are secured before her defence is mounted, which tells you what she values and confirms that this was never about a meal.
Bajie's entrance restores the usual division of labour: Sha Monk minds the luggage and the horse, Bajie goes to 幫打, help with the hitting. The novel nearly always parks them in these places, and the flatness of the arrangement is half the comedy — a demon of genuine power is met by two brothers bickering over who swings first.