一個大窟窿 A Great Hole in the Door
此間乃妖精住處，師父必在他家也。」那獃子仗勢行兇，舉釘鈀盡力築將去，把他那石頭門築了一個大窟窿，叫道：「妖怪，快送出我師父來，免得釘鈀築倒門，一家子都是了帳。」此间乃妖精住处，师父必在他家也。」那呆子仗势行凶，举钉钯尽力筑将去，把他那石头门筑了一个大窟窿，叫道：「妖怪，快送出我师父来，免得钉钯筑倒门，一家子都是了帐。」
逐句解 Line by line
This is where the fiend lives, and the master is certain to be in his house."
Wukong is right, though he is about to spend a long time being told otherwise. 他家, his house, is a slightly domestic word for a cannibal's cave, and the novel uses it deliberately — the fiends in this chapter keep house, hold meetings and argue about recipes.
The Idiot, with somebody at his back to embolden him, turned savage, swung his rake with all his force and drove it in, punching a great hole in that stone door of theirs, and bawled, "Monsters! Send my master out this instant, or my rake will bring the door down and the whole household will be settled once and for all."
仗勢行兇 is throwing your weight about because somebody stronger is standing behind you, and it is precisely and unkindly accurate about Bajie. 築倒 takes 倒 as dǎo, the falling sense, for a door battered flat. In 一家子, the whole household, 子 is zi, the unstressed everyday ending. And 了帳, to close the account, takes 了 as liǎo, to finish — a bookkeeping term used as a threat, the way English says settle up.
Bajie threatening a household with double-entry bookkeeping is very much this novel's sense of humour. Closing the accounts means killing everybody inside, and he reaches for the ledger because that is the most final-sounding phrase he knows.
The phrase about throwing your weight around deserves attention, because the narrator is the one using it, not another character. The novel is telling us plainly that Bajie is brave when Wukong is watching, and it does so in the same breath as it lets him do something genuinely impressive.