上黿之背 Onto the Turtle's Back
老黿卻才負近岸邊，將身一縱，爬上河崖。眾人近前觀看，有四丈圍圓的一個大白蓋。行者道：「師父，我們上他身，渡過去也。」三藏道：「徒弟呀，那層冰厚凍，尚且邅迍，況此黿背，恐不穩便。」老黿道：「師父放心。我比那層冰厚凍，穩得緊哩，但歪一歪，不成功果。」行者道：「師父啊，凡諸眾生，會說人話，決不打誑語。」教：「兄弟們，快牽馬來。」老鼋却才负近岸边，将身一纵，爬上河崖。众人近前观看，有四丈围圆的一个大白盖。行者道：「师父，我们上他身，渡过去也。」三藏道：「徒弟呀，那层冰厚冻，尚且邅迍，况此鼋背，恐不稳便。」老鼋道：「师父放心。我比那层冰厚冻，稳得紧哩，但歪一歪，不成功果。」行者道：「师父啊，凡诸众生，会说人话，决不打诳语。」教：「兄弟们，快牵马来。」
逐句解 Line by line
The old turtle then bore himself close to the bank, gave a heave of his body, and clambered up onto the river-cliff.
老黿 黿 (yuán); 將身一縱 將 jiāng, disposal coverb. The turtle hauls himself ashore to be measured by the astonished villagers.
The people came near to look, and saw a great white shell four zhàng round in circumference.
觀看: 觀 guān, 看 kàn. 四丈, kept untransliterated as four zhàng — some forty feet round, an enormous creature. 圍圓, in circumference.
Pilgrim said: "Master, we will get up on his body and cross over."
上他身, to mount his body. Wukong proposes the turtle as their ferry, and the master's fear supplies the block's tension.
Tripitaka said: "Disciple, even that thick ice of the frozen layer was hard going and slippery; how much less safe will this turtle's back be?"
三藏 藏 zàng; 那層冰 deictic 那 nà; 黿背: 黿 (yuán), 背 bèi, the noun "back." 邅迍 (zhān zhūn), a binome for stumbling, hard going. The master recalls the treacherous ice of chapter 48.
The old turtle said: "Set your mind at rest, master.
老黿 黿 (yuán). The turtle answers the master's fear directly, contrasting his own steadiness with the ice.
I am far steadier than that thick ice of the frozen layer. If I so much as tilt a hair's breadth, I do not accomplish the fruit of merit."
那層冰 deictic 那 nà; 穩得緊 得 dé; 哩 the vernacular final particle li. 功果, the fruit of merit — the turtle stakes his own cultivation on carrying the pilgrims safely.
Pilgrim said: "Master, among all living creatures, one that can speak human speech will surely not tell a lie."
決不打誑語: 誑 kuáng, to deceive; 打誑語, to tell a lie. This is the principle in plain form — human speech is a token of trustworthiness — and it is Wukong's answer to his master's fear, though he himself demanded an oath of the same creature two blocks ago.
He gave the order: "Brothers, be quick and lead the horse over."
教 jiào, causative "ordered." The block ends with the pilgrims moving to mount — the crossing about to begin.
The block is a study in the difference between the two crossings of the Tongtian. In chapter 48 the pilgrims crossed on ice, which betrayed them — it cracked, and the demon took the master down into the water. Tripitaka remembers this exactly, and his fear of the turtle's back is a fear of being betrayed by a surface a second time: 那層冰厚凍，尚且邅迍, even the thick ice was treacherous. The turtle's answer meets the fear on its own terms — he is steadier than the ice, and stakes his cultivated merit on it — and the contrast is pointed: the dead ice failed them, the living creature will not.
Wukong's reassurance carries a quiet irony the chapter has set up with care. He tells his master that a creature which can speak human words 決不打誑語 — will surely not lie — and this is offered as sufficient ground for trust. Yet two blocks earlier Wukong himself did not find it sufficient: he made the same turtle swear an oath to Heaven, on pain of dissolving into blood. The principle he now states to calm Tripitaka is one he did not act on when his own suspicion was up. The novel does not remark on the inconsistency; it simply lets Wukong be both the suspicious interrogator and the trusting reassurer, as the moment requires, which is true to his character throughout.