三指三噤 Three Points and Three Shudders
眾怪都不看見。二魔用手指道：「那不是？」那三藏就在馬上打了一個寒噤；又一指，又打個寒噤。一連指了三指，他就一連打了三個寒噤。心神不寧道：「徒弟啊，我怎麼打寒噤麼？」沙僧道：「打寒噤想是傷食病發了。」行者道：「胡說，師父是走著這深山峻嶺，必然小心虛驚。莫怕，莫怕，等老孫把棒打一路與你壓壓驚。」众怪都不看见。二魔用手指道：「那不是？」那三藏就在马上打了一个寒噤；又一指，又打个寒噤。一连指了三指，他就一连打了三个寒噤。心神不宁道：「徒弟啊，我怎么打寒噤么？」沙僧道：「打寒噤想是伤食病发了。」行者道：「胡说，师父是走着这深山峻岭，必然小心虚惊。莫怕，莫怕，等老孙把棒打一路与你压压惊。」
逐句解 Line by line
Not one of the fiends could see it.
都不 (dōu bù), "not one of them" -- 都 is the totalizing dōu, "all." Only the captain has the eye for an aura. His troops are looking straight at it and seeing sky.
The second fiend pointed with his hand and said: "Is that not he?"
Now 那 is the pointing nà, "that one there" -- set it against the question-word nǎ a few lines above and the pair is complete. 用手指, "pointed with his finger."
At that, Tripitaka, up on his horse, gave a cold shudder; another point, another shudder.
寒噤 (hán jìn) is a cold shiver, the kind that runs through you without warning. What makes the moment eerie is the mechanics: the demon's finger works on the master's body directly, so his flesh answers the aim before his mind knows he is a target.
Three points in a row, and three shudders in a row he gave.
一連 (yì lián), "one after another, without a break." Three points, three shudders. The tripling has the insistence of folk omen, and it is the shape the whole chapter keeps returning to -- three mountains are coming.
Uneasy in mind and spirit, he said: "Disciples — why is it I keep shuddering with cold?"
心神不寧 (xīn shén bù níng), "heart and spirit unquiet," is still the ordinary phrase for being unable to settle. Tripitaka feels the omen and cannot name it; the 麼 (me) at the end marks the puzzled question.
Sha Monk said: "The shivering is likely an attack of indigestion coming on."
傷食 (shāng shí) is "food-injury," indigestion; 病發 (bìng fā), "the complaint breaking out." Sha Monk supplies the flat, sensible misreading: you have eaten something.
Pilgrim said: "Nonsense — Master, walking these deep hills and steep ridges, is bound to take fright at shadows out of caution.
胡說 (hú shuō), "nonsense, rot." 走著 (zǒu zhe) takes the 著 of an action still running -- in the course of walking. 虛驚 (xū jīng) is a fright at nothing, a false alarm.
"No fear, no fear — let old Monkey ply his cudgel the whole way along and beat the fright out of you."
壓驚 (yā jīng) is to settle someone's nerves after a shock -- literally to press the fright down. Doubling it into 壓壓驚 makes it casual and playful, "give your nerves a good settling." 與你 (yǔ nǐ), "for you." The proposed medicine is a cudgel display, which tells you everything about the physician.
The chapter's central omen arrives in threes: three jabs of the demon's finger, three cold shudders in the master's body. It is dramatic irony at full stretch, since Tripitaka's flesh knows it has been marked while his mind gropes about for a cause -- and the three answers stage the three temperaments neatly. Sha Monk offers indigestion. The master can only ask why. Pilgrim alone senses that the trouble is nerves rather than stomach, though he puts it down to the scenery.
Pilgrim's remedy is entirely his own: not prayer, not vigilance, but a display of the iron cudgel the whole way along, to beat the fright out. It reassures the master and it cues the routine that opens the next scene, where the flourish will very nearly unman the demon watching from the peak.