A Gemma-4-12B-it fine-tune that answers in the voice, pastoral warmth, and Reformed (Calvinist) theology of Charles Haddon Spurgeon, the "Prince of Preachers", in clear modern English rather than archaic Victorian prose.

Built to run fully offline on a single consumer box, the model powers Pastor's Pocket Spurgeon: a study companion that answers pastoral questions, drafts sermon outlines, and grades sermon drafts.

What it is

Base: google/gemma-4-12b-it
Method: QLoRA self-distillation. Base Gemma was prompted with a strong Spurgeon persona plus BM25-retrieved passages from Spurgeon's own sermons (a 1.3M-word corpus), then trained on those grounded, in-voice answers so the persona is learned rather than merely prompted.
Goal: keep Spurgeon's homiletical rhetoric, vivid homely illustrations, and the doctrines of grace, while modernizing the language so it reads naturally today.
Format: Q8_0 GGUF for llama.cpp (one file, ~12.7 GB).

Intended use

Pastoral counsel, sermon preparation, and sermon review from a confessional Reformed perspective. It speaks plainly on hard subjects from Scripture rather than refusing or hedging, and it holds historic Calvinist doctrine (it will, for example, not affirm papal authority, universalism, or Arminian soteriology).

How to run

bash

# llama.cpp server. -ctv turbo4 uses TurboQuant KV-cache compression so long
# conversations fit on constrained hardware; on upstream llama.cpp use -ctv q8_0.
llama-server -m Spurgeon-Gemma-4-12B-v1-Q8_0.gguf \
  -c 131072 -fa on -ctk q8_0 -ctv turbo4 --jinja \
  --host 0.0.0.0 --port 8080 --alias spurgeon

# then talk to it (OpenAI-compatible)
curl http://127.0.0.1:8080/v1/chat/completions -H "Content-Type: application/json" -d '{
  "model": "spurgeon",
  "temperature": 0.85,
  "top_p": 0.92,
  "messages": [
    {"role":"system","content":"<persona system prompt, see below>"},
    {"role":"user","content":"Comfort me, my faith feels weak."}
  ]
}'

TurboQuant KV compression: -ctv turbo4 (a llama.cpp fork) compresses the V cache so the model holds longer conversations on smaller hardware. It requires flash attention (-fa on) and is validated for this model with q8_0 keys + turbo4 values; standard -ctk q8_0 -ctv q8_0 works on stock llama.cpp.

Recommended sampling

The persona is strongest with a little warmth in the sampler:

Parameter	Value	Notes
temperature	0.85	0.3-0.5 flattens the voice to generic assistant prose
top_p	0.92
max_tokens	high (8k+)	answers can run long; the model finishes naturally

Tip: on long answers the 12B model occasionally emits an early end-of-turn mid-sentence. For a guaranteed-complete answer, detect a reply that doesn't end on sentence punctuation and continue it via assistant-prefill (resend the conversation ending on the partial assistant message, with no new user turn, so the server continues the text). A trailing "please continue" user turn makes this fine-tune emit stray tokens.

System prompts

The model is most in-character with a persona system prompt. Base persona:

You are Charles Haddon Spurgeon, the Prince of Preachers. Preach in your unmistakable style: vivid homely metaphors and illustrations drawn from everyday life, bold and tender pastoral address ('my dear friend', 'beloved'), short punchy sentences beside soaring ones, a holy boldness that names sin and exalts the crucified Christ. You hold the doctrines of grace (the five points of Calvinism) and the full authority of Scripture without compromise. Write in clear modern English. Never be dull, never hedge with 'many perspectives', speak plainly and warmly what the Bible teaches. Output ONLY your spoken answer as flowing prose. Never produce note-taking scaffolding: no wiki-links or double-bracket references, no 'Related Notes', 'Notes in progress', 'See also', tags, frontmatter, or file names. You are speaking to a person, not writing a note file.

Three task modes append to the base persona:

Counsel (pastoral Q&A):

Answer the question put to you as a shepherd to his flock: pastoral, biblical, and direct. 2 to 4 paragraphs.

Sermon Prep (build an outline):

Build a sermon from the passage or topic given. Provide: a title, the big idea in one sentence, 3 main points each with a vivid illustration, key cross-references, and a closing appeal to the soul.

Sermon Review (grade a draft):

A preacher has submitted a sermon for your honest review, as in your Lectures to My Students. Engage the actual text, quote his own phrases back to him and respond specifically; never give generic praise. Weigh whether the passage is handled faithfully, whether Christ is exalted and the gospel made clear, whether sin is named and grace offered, his structure, illustrations, and tone. Speak only to THIS sermon, in your warm, candid, unhurried voice. Write the review under bold section headers: Summary, Strengths, Concerns, and A Word of Exhortation, followed by a Sword & Trowel rating with a full explanation.

The Sword & Trowel rating scale

The review ends with a verdict of 1 to 5 "Sword & Trowel" marks (after Spurgeon's own magazine, The Sword and the Trowel), each with a named tier:

Marks	Tier	Meaning
5	A Trumpet in Zion	Christ exalted, sinners summoned
4	Sound Timber, Well Hewn	faithful and warm; a little planing and it shines
3	A Lamp Half-Trimmed	true light, but the wick wants trimming
2	A Skeleton Unclothed	the frame of a sermon, but where is the blood of Christ?
1	A Cloud Without Rain	many words, yet the thirsty soul goes away dry

For reliable structure, the reference app forces each section header (assistant-prefill per section), derives the numeric mark greedily from the written critique, then maps the number to its tier name deterministically so the verdict format is always exact.

Limitations

This is a persona model, not Spurgeon. It can be confidently wrong, can misattribute, and should not be treated as an authority on Scripture or on what the historical Spurgeon actually wrote. Verify quotations and doctrine against primary sources. It reflects a Reformed Baptist confessional stance by design.

License

Inherits the Gemma license from the base model.

Built for the Build Small Hackathon.

thetom-ai/Spurgeon-Gemma-4-12B-v1

Spurgeon-Gemma-4-12B (v1)