What does the character gain from her religion? What use is religion to the character?
First, all characters gain the things anyone gains from religion in our world - comfort in adversity, confidence in the self, certainty of purpose, moral guidelines, and the like.
Second, Believers and Strong Believers can be the beneficiary of miracles.
When working in accord with the dictates of her religion, and against something antithetical to that religion, a Believer gains an Edge. In the same circumstances, a Strong Believer gains two Edges. Players may declare their characters’ religions strengths when they decide on a religion.
Practitioners are those who follow a religion, but do not hold to it in daily life. When pushed, a Practitioner tends to think of himself rather than his religion, and do whatever is of most benefit at the time. Attendance at worship is spotty, rituals are skimped, and belief is shallow. Many followers of religion are Practitioners.
Believers are those who hold to a religion in more than name only. They practice rituals even when inconvenient, try to hold themseves to the precepts of their religion in their daily life, and would only deny their religion for subterfuge. There are always vastly more Believers than Strong Believers in any religion.
Strong Believers push their relationship with their religion to another level. They practice rituals even when dangerous, never deviate from the precepts of their religion in their daily life, and would never deny their religion for any reason.Strong Believers are the rarest of adherents for all religions.
Judging Character Actions
The GM must judge the characters’ actions in light of their declared level of belief. If a character does not live up to expectations, the GM should downgrade the status of the character, after informing the player. If, on the other hand, the character seems to be more in accord with a higher level of adherence, the GM should inform the player, and - if the player agrees, move the character up a level.
Miracles are always entirely subjective - they always take the form of something which can be attributed to luck, chance, psychological manipulation, or willpower. A disease can spontaneously remit. A character can survive poisoning. A million to one shot can be made. An earthquake can open the walls of a cell. The impact should be major!
Once per campaign, any Believer can ask for a miracle. Unless there are insurmountable reasons to say no, or the miracle would violate the precepts of the religion, the GM should grant this. If denied by the GM, the character may ask again in other circumstances. A Strong Believer may ask for an additional miracle, that is two miracles per campaign, under the same conditions.