Hi Rett,

r> The reference is Sp I, page 6, line 2, which I believe is to the PTS
r> edition. There's a chance it's to another book abbreviated Sp. The
r> quotation is "pure adhammo dippati". What I need is a little bit of
r> context: a line or so of text before and after the quotation.

It's:

Evamaadinaa nayena navaanupubbavihaaracha.labhi~n~naappabhede
uttarimanussadhamme attanaa samasama.t.thapanena ca anuggahito,
tassa kima~n~na.m aa.na.nya.m bhavissati; nanu ma.m bhagavaa
raajaa viya sakakavaca-issariyaanuppadaanena attano
kulava.msappati.t.thaapaka.m putta.m
'saddhammava.msappati.t.thaapako me aya.m bhavissatii'ti mantvaa
iminaa asaadhaara.nena anuggahena anuggahesii"ti cintayanto
dhammavinayasa"ngaayanattha.m bhikkhuuna.m ussaaha.m janesi.
Yathaaha-

"Atha kho aayasmaa mahaakassapo bhikkhuu aamantesi- 'ekamidaaha.m,
aavuso, samaya.m paavaaya kusinaara.m addhaanamaggappa.tipanno
mahataa bhikkhusa"nghena saddhi.m pa~ncamattehi bhikkhusatehii"ti
(dii. ni. 2.231) sabba.m subhaddaka.n.da.m vitthaarato
veditabba.m.

Tato para.m aaha-

--> "Handa maya.m, aavuso, dhamma~nca vinaya~nca sa"ngaayeyyaama. Pure
adhammo dippati, dhammo pa.tibaahiyyati; avinayo dippati, vinayo
pa.tibaahiyyati. Pure adhammavaadino balavanto honti,
dhammavaadino dubbalaa honti; avinayavaadino balavanto honti,
vinayavaadino dubbalaa hontii"ti (cuu.lava. 437).

Bhikkhuu aaha.msu- "tena hi, bhante, thero bhikkhuu uccinatuu"ti.
Thero sakalanava"ngasatthusaasanapariyattidhare
puthujjana-sotaapanna-sakadaagaami-anaagaami-sukkhavipassakakhii.naasava-
bhikkhuu anekasate anekasahasse ca vajjetvaa
tipi.takasabbapariyattippabhedadhare pa.tisambhidaappatte
mahaanubhaave yebhuyyena bhagavataa etadagga.m aaropite
tevijjaadibhede khii.naasavabhikkhuuyeva ekuunapa~ncasate
pariggahesi. Ye sandhaaya ida.m vutta.m- "atha kho aayasmaa
mahaakassapo ekenuunaapa~nca-arahantasataani uccinii"ti (cuu.lava.
437).

Or:
http://www.tipitaka.org/tipitaka/vin01a/vin01a-2.html

Best regards,
Dimitry

http://dhamma.ru/sadhu/