Holy Magic is the magic of the Gods and Goddesses, of which there are many. They are pure, perfect beings of light and goodness, and all true Holy Clerics should aspire to be as close to Godly as possible. This is easier inside the temple than out.
The Gods and Goddesses are busy with their own affairs and pay little attention to mortal cares. So if you're an asshole, you can still be a Holy Cleric. You just can't cast any Unholy spells. Gods and Demons alike will notice if someone switches sides, and will not be pleased. To get back in the Gods' good graces after being corrupted takes a hell of a lot of purifying, and usually requires you stick around the temple for quite some time, to prove your devotion and remove you from temptation to fall again. Even then, expect to be watched by others of your order.
Still, there are perks to being a Holy Cleric. Healing spells for yourself and others, protection spells, even divine intervention (read: smiting) at the higher levels - there's almost always a need for a Holy Cleric. A wandering Holy Cleric won't have much in the way of money (at least, s/he SHOULDN'T...) but will never want for a place to sleep, food to eat, a helping hand up should s/he fall.
Keep in mind that being a Holy Priest/Cleric only means you can't cast Unholy spells. Your personality is still whatever you decide, although most newly-vested, fresh from the temple clerics are likely to be more righteous (and/or self-righteous) than those who have been wandering the world a spell.
Holy Priests/Clerics are less likely than other magic-users to take up other magic schools, but it's not unheard of.
A vested Cleric/Priest/Priestess (one who has graduated from a holy temple; the term "cleric" is used for a priest/priestess who is not living in a temple - either wandering, or living on their own) is Level 4; Levels 1-3 are the still-learning stages of neophyte, apprentice, and journeyman (respectively). Levels 5-8 are simply progressions and bring with them no change in rank on their own (although temples may promote/demote at their discretion). Level 9 is High Priest, and Level 10 is Holy Master. The difference is that High Priests are generally in charge of a temple, maybe overseeing two or three if they're close together. Holy Masters are more likely to be hermits or wandering do-gooders, eccentric but righteous. Even a Level 1 neophyte can still see a white sort of "glow" outlining Holy or Blessed objects or people, but cannot detect the "aura" or "glow" of other magic types unless they've also studied those. The "glow" is not visible on oneself unless one is actively working magic at the time, and fades when the spell is cast or otherwise ends.
As with most magic schools, you buy your Level of magic with points. In the case of Holy/Unholy spells, your level decides what spells you know and what strength those spells are. Buying level 1 costs 6 points, level 2 costs 5, levels 3 - 8 cost 4 points each, level 9 takes 5 points and level 10 takes 6 again. Keep in mind that if you take Holy Magic, you CANNOT take Unholy Magic.
Holy Cleric/Priest Package (12 points) (most actual Paladins are vested Clerics/Priests as well, they just need to take the appropriate weapon skills):
With GM permission, you may swap Temple Code at any appropriate time (including character creation) for an appropriate other disadvantage. For example, you've attempted to hold to Temple Code, but you've succumbed to the temptation of alcohol - over and over and over again. The GM allows you to swap "Disadv. Temple Code" for "Disadv. Addiction - Alcohol". If you swap, you get no additional bonus points, nor incur any sort of penalties - it's considered an even exchange, no matter what you swapped it for.
Also, though it should go without saying, if you are still living at the Temple at the beginning of the story, you must take the Temple Code disadvantage.
Also known as Temple Code. These rules are enforced more or less strictly depending on the temple. For example, DiCi Temple is fairly lax on nearly all the rules whereas Milleton Temple is very strict. Most temples fall somewhere in between. Holy Temples generally grow plants for consumption, and while they do not normally raise animals, they often care for horses, cats, and dogs.
It should be noted that most priests-turned-clerics (remember that if you live inside the temple, you are a priest; outside the temple, a cleric) break almost all these rules as soon as they get free of temple constraints. Paladins and the especially devout clerics may slowly slide into some temptations, but they usually fight it the whole way.
And yes, marriage is allowed. Married priests/clerics/paladins are encouraged to stay at the temple to raise their families, but most move a short ways away. If they've married an Unholy devotee, they move very far away.
.:Holy Spells Alphabetically:.