Let good and ill be, for a moment, put out of mind; let flourishing and withering trouble the heart not at all.

Chapters often open with a set song rather than a scene, and this is one of them: a lyric to the tune 西江月, "The West River Moon," whose two verses each run six syllables, six, seven, six. The advice is to let opposites go. 一時 yì shí is "for a moment," or "all at once"; 都 here is dōu, "at all, in the least," which sharpens the refusal that follows it in 不關心, "let it not touch the heart." The song is stating the chapter's theme before a single thing has happened.

Dark and bright, hidden and shown — leave them to rise and sink as they will.

Two pairs of opposites in four characters: 晦明 dark and bright, 隱現 hidden and shown. Then 任浮沉, "let them float or sink" -- stop swimming against the current. Nothing tricky in the readings here.

As one's lot allows, eat when hungry and drink when dry.

隨分 suí fèn means "according to your allotted share," so, contentedly -- a stock phrase in Chan writing. 分 is fèn, the "portion, lot" reading, not the everyday fēn of "divide" or "a tenth." 饑餐渴飲, "eat when hungry, drink when thirsty," is the old image of doing the natural thing at the natural time and nothing more.

When the spirit is still — clear, limpid, forever at rest; but let it cloud and darken, and at once the demon breaks in.

Here the song turns, and this is the hinge of the whole Red Boy episode. A quiet mind (神靜湛然常寂, still and clear and at rest) is safe; the moment it clouds over (昏冥), the demon walks in. 魔 is the ordinary word for a demon and also the Chinese rendering of Sanskrit *mara*, the tempter -- so the line reads at once as a warning about monsters and a warning about one's own state of mind. Hold that thought: the fire that nearly kills Wukong later is exactly this 魔, let in.

The Five Phases stumble and lurch, and the grove of Chan is broken.

五行 wǔ xíng, the Five Phases -- metal, wood, water, fire, earth -- the five-part scheme Chinese thought used to explain how anything turns into anything else. 蹬蹭 dēng cèng is to stumble and lurch. 禪林, "the grove of Chan," pictures the disciplined mind as a monastery wood, so the line has the Five Phases blundering through it and knocking it flat. Watch for this line to come literally true: the demon's fire is raised from five carts set out by the Five Phases. 行 is xíng here, never héng.

Let the wind but stir, and a killing chill must surely follow.

The closing line. Any stir of wind (風動) must bring a killing cold (寒凜) after it -- the small first movement that ruins stillness. It lands the song back where it started.