Most religions teach at least a modicum of self-reliance – faith that your god will sustain you through your trials, but the trials themselves are up to you to endure and figure out. GURPS Powers: Divine Favor offers a fairly comprehensive framework for characters who are divinely empowered by God, gods, powerful spirits, etc. But how to represent the former using the latter? Here are a few ideas.
A Little Dollop Will Do You
Perhaps the easiest way borrows some mechanics from GURPS Power-Ups 5: Impulse Buys. Each game session that goes by where a paragon doesn’t call on their god they get a single point to their “petition pool.” This rate is doubled if a paragon goes through an entire session without using any divine aid – including Learned Prayer. You may have at most half your Divine Favor in such petition points. The next time you call upon the divine (but not the next time you use a Learned Prayer) make your petition roll as normal, but you may temporarily increase your Divine Favor level by +1 per two points spent.
Reversed Reaction Rolls and Appearance Rolls
Normally, in Powers: Divine Favor you make your petition roll on your Divine Favor and then make a reaction roll. The first decides if your god intervenes or not and the second decides how they intervene. The GM may alternatively roll the reaction roll first and ask the player what exactly sort of miracle they are praying for, then adds a bonus of +1 on the petition roll for every reaction level shift down or a -1 penalty for every reaction level shift up – to minimum of +4 or -4.
For example, if you are praying for a minor blessing and get an excellent reaction your petition roll for your miracle would get a +4.
Picking Over the Bones
Both ideas are interesting and have their own merits, but comes with the downside of complicating play a bit – a tradeoff that may be worth it. The idea of abstaining from your powers to be able to call on them when you really need them appeals to me greatly. I suppose you could also do the opposite in the first method – the more you petition the more points you lose from your pool, but that’s probably too harsh.