蒼蠅探袋 A Fly on the Bag
好行者，假中又假，虛裡還虛：即拔一根毫毛，吹口仙氣，變作個包袱一樣；他的真身卻又變作一個蒼蠅兒，釘在門樞上。只聽得八戒在那裡哼哩哼的，聲音不清，卻似一個瘟豬。行者嚶的飛了去尋時，原來他吊在皮袋裡也。行者釘在皮袋上，又聽得他惡言惡語罵妖怪長，妖怪短：「你怎麼假變作個觀音菩薩，哄我回來，吊我在此，還說要吃我？有一日我師兄：好行者，假中又假，虚里还虚：即拔一根毫毛，吹口仙气，变作个包袱一样；他的真身却又变作一个苍蝇儿，钉在门枢上。只听得八戒在那里哼哩哼的，声音不清，却似一个瘟猪。行者嘤的飞了去寻时，原来他吊在皮袋里也。行者钉在皮袋上，又听得他恶言恶语骂妖怪长，妖怪短：「你怎么假变作个观音菩萨，哄我回来，吊我在此，还说要吃我？有一日我师兄：
逐句解 Line by line
Fine Pilgrim! — false within false, feint within feint: he plucked a single hair, blew on it a breath of immortal air, and made it into a bundle just the same;
假中又假, 虛裡還虛 -- false within false, feint inside feint. He plucks a hair and makes it into a copy of the bundle to leave in his own place, so that if anyone checks, the bundle is still there. Wukong's hairs are one of his standing tricks, and here he uses one purely as an alibi.
while his true body changed into a housefly and settled on the door-pivot.
And the real body becomes a housefly on the door-pivot. This is his standard reconnaissance form throughout the novel -- small, ignorable, and able to sit anywhere.
He heard Eight Rules moaning and groaning away there, his voice indistinct, for all the world like a sick pig.
What he hears is moaning. 卻似一個瘟豬 -- for all the world like a sick pig. 瘟 wēn is a plague or murrain, so this is a pig with the sickness in it. Given who is making the noise, the comparison is doing double duty, and the novel plainly enjoys it.
The Pilgrim, with a buzz, flew off to find him — and there he was, hung up in the leather bag.
嚶 yīng is the sound of a fly -- a buzz written down. He follows the noise and finds his brother hanging in the leather bag.
The Pilgrim settled on the bag and heard him cursing the demon up hill and down dale in the foulest terms: ‘How dare you falsely change into a Guanyin Bodhisattva, trick me back here, hang me up, and still say you mean to eat me?
罵妖怪長, 妖怪短 is a construction meaning to go on and on about someone -- demon this, demon that. And then Bajie's actual complaint, which is a good one: you disguised yourself as a Bodhisattva, tricked me home, strung me up, and you still say you are going to eat me. The outrage is at the discourtesy as much as the danger.
One day my elder brother will:
The lead-in to a short boast in verse. Note that nothing in the bag has stopped him composing.
greatly deploy his boundless Equal-to-Heaven dharma, and seize every insolent demon on the mountain at a stroke;
The prophecy: my elder brother will bring out his boundless Equal-to-Heaven power and take every demon on this mountain at a stroke. 無量, boundless, is a word borrowed from Buddhist usage, and Bajie applies it to Wukong without hesitation.
untie the bag and let me out, and give you a thousand rake-blows to my heart's content.’
And the reward he wants for himself: let me out and let me hit you a thousand times with my rake. 趁心 means to one's satisfaction. It is a completely honest account of what would make him happy.
Wukong's infiltration is layered: a hair turned into a duplicate bundle left lying where the real one was, and his true self as a fly on the door-pivot. Then he follows the sound of groaning to the bag holding his brother.
What he overhears is Bajie, trussed up and promised to the steamer, cursing steadily and then composing a short poem about how his elder brother is going to come and flatten everyone. There is no doubt in it anywhere. Bagged, hung from a beam, and scheduled to be eaten, he simply assumes rescue is coming.
And it is, and it is sitting on the bag. Neither of them knows what the other is doing, and the scene is much better for the fact that Wukong never says so.