暗念真言 The Fillet Spell Fails
菩薩喚木叉與善財上前，悄悄吩咐：「你一個幫住一個，等我暗念緊箍兒咒，看那個害疼的便是真，不疼的便是假。」他二人果各幫一個。菩薩暗念真言，兩個一齊喊疼，都抱著頭，地下打滾，只叫：「莫念，莫念。」菩薩不念，他兩個又一齊揪住，照舊嚷鬥。菩萨唤木叉与善财上前，悄悄吩咐：「你一个帮住一个，等我暗念紧箍儿咒，看那个害疼的便是真，不疼的便是假。」他二人果各帮一个。菩萨暗念真言，两个一齐喊疼，都抱着头，地下打滚，只叫：「莫念，莫念。」菩萨不念，他两个又一齐揪住，照旧嚷斗。
逐句解 Line by line
The Bodhisattva summoned Mokṣa and Sudhana forward and quietly instructed them: "Each of you take hold of one of them. Let me silently recite the Tight-Fillet Spell; watch which one suffers pain — that is the true one — and the one who does not is the false."
The best test in the cosmos, and the Bodhisattva sets it up like a doctor testing a reflex: hold one each, watch which one flinches. 箍兒 in 緊箍兒咒 takes the light er ending. And 看那個害疼的 uses 那個 to ask which one — nǎ, not the pointing nà of 那菩薩.
The two of them did indeed each take hold of one.
幫住, to hold fast, is kept at bāng across the project.
The Bodhisattva silently recited the true words. Both of them cried out in pain together, both clutched their heads and rolled upon the ground, crying only: "Stop the recitation, stop the recitation."
Both heads hurt. 都抱著頭 takes zhe, the ending that keeps the clutching going. 真言 is the Sanskrit mantra, the spell under its dignified name.
The Bodhisattva stopped reciting, and the two of them at once seized each other again and brawled on as before.
照舊, just as before. The spell has changed nothing, and the narration marks the two of them going back to it as a return to normal rather than as a worsening.
The Tight-Fillet Spell ought to settle everything. It is the one instrument in the novel keyed to Wukong personally: the band was fitted to his skull and nobody else's, and the pain it causes is targeted rather than general. It is the equivalent of checking a fingerprint. The Bodhisattva's reasoning is sound and this is the best test available anywhere in the cosmos.
It fails because both heads hurt. The novel reports the fact and offers no explanation, leaving the reader to sit with an implication considerably stranger than the imposture itself. Copying an appearance is one thing; copying somebody's private, physically enforced bond to a specific magical object is another. Whatever the false Pilgrim is, the resemblance goes a long way below the skin.
照舊嚷鬥 ends the episode with a shrug. The most powerful discriminating instrument in existence has been fired off, and the two go back to brawling exactly as they were, as though nothing had been tried. The Bodhisattva has now failed twice — once by looking, once by testing — and the chapter has sixty-five passages still to run.