For those who haven't read past posts here, I use this space to kind of think out loud. My all time favorite classes in AD&D 1E is Clerics.
I am not of the thinking that a Cleric in AD&D 1E is some meek and mild pastor of a church or temple wagging his finger at scofflaws. Instead, I see the cleric as a "Holy Avenger" (or unholy as the case may be).
This is not to say that all clerics must be christian type Knight Templars, though that is certainly one good example. The Cleric has a mission given to him/her by the deity they serve to carry out.
While the Fighter classes are typically oriented toward open warfare, the Cleric is a soldier of faith. In fact, it is their faith that seems to me to be their greatest strength (or weakness).
Many talk about the weapons restrictions on clerics BtB and some feel it is too restrictive unnecessarily. I personally tend to house rule that clerics can use any weapon that is the preferred weapon of their deity. That doesn't mean I let them wander around using any weapon they can buy or pick up though. Their weapon of choice is very important as it is a reflection of the faith in their deity.
I let them have any one weapon that is the preferred of their deity regardless of whether it is on the restricted table or not. Because it is their deities weapon, they can use that weapon with a bonus for each 5 levels they gain. In doing so, I also house rule that they get no benefit of using otherwise enchanted weapons to kind of balance things out a bit.
The exception to that are clerical specific enchanted weapons that have been "blessed" (or cursed) by their deity.
I said earlier that I believe faith is the Clerics greatest weapon. I created a "faith check" for clerics. The stronger their faith, the greater ability they have to succeed. The lesser their faith, the lesser capable they are of wielding their deity's powers. I admit to taking this idea from books like "The Exorcist" and "'salem's Lot" to name a couple. The concept is pretty well established in history though.
Having thought of having Clerics make "Faith Checks" then suggested to me that there were times when such a check would be required. So I created a table that showed when a Cleric would be required to make a faith check, both to benefit as well as to penalize.
For example, one situation where a faith check would arise is when confronted with a diametrically opposed enemy that is more powerful than the Cleric.
If the 4th level Cleric is Lawful Good and he comes up against a 9th level demon for example, a "Faith Check" is in order. This may not be required if it were some "normal" opponent because that opponent is not seen as "the Enemy" and is seen as "just another" opponent. The situation against the higher level demon could shake the faith of the Cleric, making him less able to wield his deity's power and thus less likely to succeed in a battle of swords or a battle of spirit, such as an exorcism, thus resulting in a penalty.
However, their faith may not be shaken at all. This roll result would mean that things stay the same.
Sometimes when confronted in such a situation, a Clerics faith can grow and be eager to be the champion his deity demands of him to be, in which result, a bonus would apply.
The same thing applies for tasks or challenges that a cleric might find overwhelming to them. In attempting to cast a spell they have never cast before that is a high level spell, a roll might be warranted to see if their faith is affected. If their faith is shaken and they might not feel "sure" their deity will grant them such power or (deity forbid) not be capable of imparting such power, a "faith check" will be warranted.
Does a faith check happen in every task or challenge they face? Of course not.
Certain things can automatically force a faith check. Say a Lawful Good cleric encounters a good or neutral opponent in combat due to a variety of possible reasons. The Good Cleric will not necessarily be up for wholesale slaughter of such opponent. How this is role-played can lead to a faith check. If he just goes for the kill anyway, a faith check for the deity will be made when declaring intention at initiative roll.
Again, if the roll indicates the deity is in his "normal" range, the act will happen without anything significant resulting. If the roll indicates the deity has increased faith in the Cleric because of such intention, a bonus is applied. Then if the roll indicates a negative response, a penalty is the result
I use a dice roll to determine the Deity's faith in the Cleric because no man knows the mind of a deity. They may make decisions based on criteria a follower may never know or understand. So far, I think in playing Clerics this way in games, a lot of depth is added to the PC and the game itself. It leads the Players to really think about their Clerics actions and intentions as they go along.