幫幫功 Sha Monk Dispatched
獃子去了，沙僧將酒亦一飲而乾，道：「師父，那黃袍怪拿住你時，我兩個與他交戰，只戰個手平。今二哥獨去，恐戰不過他。」三藏道：「正是，徒弟啊，你可去與他幫幫功。」沙僧聞言，也縱雲跳將起去。那國王慌了，扯住唐僧道：「長老，你且陪寡人坐坐，也莫騰雲去了。」唐僧道：「可憐，可憐，我半步兒也去不得。」此時二人在殿上敘話不題。呆子去了，沙僧将酒亦一饮而干，道：「师父，那黄袍怪拿住你时，我两个与他交战，只战个手平。今二哥独去，恐战不过他。」三藏道：「正是，徒弟啊，你可去与他帮帮功。」沙僧闻言，也纵云跳将起去。那国王慌了，扯住唐僧道：「长老，你且陪寡人坐坐，也莫腾云去了。」唐僧道：「可怜，可怜，我半步儿也去不得。」此时二人在殿上叙话不题。
逐句解 Line by line
When the blockhead had gone, Sha Monk likewise drained his cup at a draught and said, 'Master, when the Yellow-Robe Ogre held you captive, the two of us did battle with him and came off only even. Now that Second Brother goes alone, I fear he will not be able to overcome him.'
Sha Monk supplies the arithmetic nobody else has done. 只戰個手平 is "fought only to a level hand," a draw; 戰不過他 is "cannot get the better of him." Two of them managed a draw, so one of them will lose — which is obvious, and which is why it takes the least talkative member of the party to say it out loud. 將 (jiāng) takes up the wine; 一飲而乾 (乾 = gān) drains it.
Said Tripitaka, 'Just so. Disciple, you may go and lend him your aid.'
幫幫功 is plain spoken Chinese — "help out with the job," lend a hand — and the doubling of 幫 makes it casual rather than formal. Tripitaka commits his second and last disciple to the fight in eight characters.
Hearing this, Sha Monk too loosed a cloud and leaped up into the air.
縱雲 is to spring onto a cloud; 跳將起去 uses 將 (jiāng) as a small directional syllable attached to the verb, giving "leaped up and away."
The king took fright and, seizing hold of Tripitaka, said, 'Elder, do sit a while and keep me company — do not you ride off on the clouds as well!'
And with both monsters gone the king discovers he does not want to be left alone after all. 慌了 is "took fright"; 扯住 is to grab and hold on. His request — sit with me a while, and do not you fly off too — is the most human line he is given.
Said Tripitaka, 'Alas, alas — I could not go half a step even if I would.' And so the two of them fell to talking there upon the hall, of which no more need be told.
可憐，可憐 is "pitiable, pitiable," and Tripitaka means himself. 半步兒 (兒 = er) 也去不得 takes 得 as the potential dé: he could not go half a step if he wanted to. 敘話不題, "talked on, of which no more is told," is the storyteller's formula for putting a thread down and picking up another.
The passage is the sober counterweight to Eight Rules' bravado. Where he has just styled himself the pilgrimage's foremost demon-queller, Sha Monk supplies the plain record of their earlier encounter: the two of them together fought the Yellow-Robe Ogre to a draw, and one alone can hardly expect to do better. It is a characteristically level-headed judgement from the steady, unglamorous member of the band, and it moves Tripitaka to send him after his brother, so the reinforcement is on its way before the battle the chapter has been building toward.
The scene ends on a last comic beat. With both his fearsome disciples aloft, the king is seized by a fresh alarm and clutches at Tripitaka — do not you fly away as well — and the master can only answer, ruefully, that he could not go half a step if he tried. The joke is at the expense of both of them: the king who cannot bear to be left alone with the trouble he has stirred up, and the entirely earthbound holy man who is the one companion he is in no danger of losing to the clouds.