There are twelve third-level spells for clerics in the Player's Handbook. Six of those were introduced in OD&D: continual light, cure disease, locate object, prayer, remove curse and speak with dead. Animate dead was in OD&D, but there it was a 5th-level magic-user spell, and not available to clerics at all. Create food & water seems to be a combination of two OD&D spells: create water (which was 4th level) and create food (which was 5th level). Cure blindness had been previously introduced as part of the Healer class in The Dragon #3. Finally, there are two spells that are all-new in AD&D: feign death and glyph of warding.
Animate Dead: This spell allows the caster to animate the bodies or bones of humans as skeletons or zombies (one per caster level). The spell does specify humans, not humanoids; by-the-book, you can't use this spell to create dwarf skeletons or orc zombies or whatever. The undead created obey the caster's commands, and last until they're either destroyed or dispelled. This raises the obvious question: can any skeletons or zombies be dispelled using dispel magic? Are all skeletons and zombies the result of an animate dead spell, or are there some that originate in different ways? The Monster Manual says that they're both magically animated corpses under the command of the one who animated them, so it looks as though animate dead is the canonical explanation for all of them. Given that it's not mentioned as a specific weakness in the Monster Manual, I'd rule against destroying them with dispel magic.
The main difference between this spell and the OD&D version is the number of undead created. Clerics in AD&D create one undead per caster level, whereas OD&D magic-users (that class being the only one with the spell available to them) could create 1d6 undead for every level over 8th. So while AD&D casters do better in the short term, OD&D casters break even around 11th level and surge ahead from there.
Continual Light: Creates a light that lasts forever (or until dispelled). It can be cast in the air, attached to an object, or cast at a creature, and in the latter case it will blind the target on a failed save. It can be reversed to cause "complete absence of light".
The main difference between this version of the spell and the one in OD&D is the area of effect: OD&D had a diameter of 24", while AD&D has a diameter of 12". (In my initial reading of the AD&D spell, I had thought that the spell created a globe of light 6 inches in radius, but obviously it's supposed to be game inches representing tens-of-feet: that's how far the light extends rather than the size of the globe itself.)
The blinding effect is a useful one, especially given the spell's permanent duration. It's about on par with the 2nd-level Illusionist spell blindness, which is fine. What's not fine is that it far outstrips the reverse of cure blindness (cause blindness, which I'll detail below).
Create Food & Water: This spell creates "one cubic foot" of food and/or water per caster level. It's odd that the spell is measured in cubic feet (I'm picturing a perfectly square block of ham), but it's done as a way to split between the creation of food and water. A second level caster, for example, could create two cubic feet of food, two of water, or one of each. Each cubic foot provides enough to nourish three people, or one horse. It seems overly complicated, but I can just about do it in my head.
What's not specified is the type of food that appears, so I'd rule that the caster can create whatever the hell he wants.
This spell is a combination of the OD&D spells create water (4th level) and create food (5th level). Both of those spells created enough to sustain a dozen men for a day, and doubled for every level the Cleric attained over 8th. Obviously the AD&D version is more versatile, but it doesn't scale up as ridiculously as the two OD&D spells did.
The 1st-level AD&D spell create water should also be noted. That spell makes 4 gallons of water per caster level, which to my eye seems more than create food & water (4 gallons would be more than enough for three people for a day). That's as it should be - specialised spells should be more effective than versatile ones.
Cure Blindness: Permanently cures "most forms" of blindness. (Nice and vague there.) The spell can be reversed as cause blindness, but that spell has some problems. Notably, it's not as good as using continual light for the same effect, because continual light works at range while cause blindness is a touch spell. Otherwise they're identical, but being able to blind someone from 120 feet away is a lot more useful.
The original version of this spell was introduced with the Healer class in The Dragon #7. That version was able to cure blindness of any sort, but wasn't reversible.
Cure Disease: This spell will cure most diseases with a touch. I'm surprised to note that the cure doesn't take effect immediately; it can take anywhere from 1 turn to 1 week to heal the target, depending on the severity and advancement of the disease. I've always played it as instantaneous.
The spell can be reversed as cause disease, which causes the target to lose 1 hp per turn and 1 point of Strength per hour, until both are at 10%.
The OD&D version of the spell cured "any form of disease", and that was pretty much the entirety of the spell description. It was reversible, but the effect of that wasn't given (though one could use the disease rules from Supplement II).
Dispel Magic: Negates various magical effects within a 3" cube. It will destroy potions, remove spells cast on creatures or items, and counter any spell-casting done within the area of effect. It has no effect on any magic items other than potions. The spell starts with a base 50% chance of success, with the chance going up if the magic to be dispelled is lower level than the caster, and going down if it is higher. It's said to be very effective against charmed creatures (though nothing mechanical is given), and it will automatically dispel the caster's own spells.
The OD&D version of the spell was for magic-users only, and was written as dispell magic. It had a range of 24", as opposed to 6" in AD&D. It also had a duration of 1 turn, whereas in AD&D the duration is "permanent". That "permanent" duration is curious. No doubt it refers to the magic being dispelled permanently, but it makes me wonder how long that 3" cube stays in effect? I'd rule it as an instantaneous flash that dispels the magic within it, then disappears.
The other big difference between the OD&D and AD&D versions of the spell is the formula used to determine the spell's success. AD&D starts at 50%, modified up or down based on the strength of the magic to be dispelled. OD&D uses a ratio of the dispeller over the original spell. If I'm doing the math correctly, it seems that lower-level casters have a better chance to dispel high-level magic in AD&D; magic of equal level will be dispelled 50% of the time in AD&D, and 100% of the time in OD&D; obviously, higher-level casters automatically succeed in OD&D, while it's a more gradual scale in AD&D. The spell was a lot more effective in OD&D.
Feign Death: This spell, making its first appearance here, puts the target into a "cataleptic state" that makes him appear to be dead. The target is fully aware, and can still smell and hear, but he can't see or feel anything. Any damage inflicted on the body is halved (which makes me wonder just how much hit point damage is based on pain), and the target is immune to paralysis and level drain (I guess he's protected by the spell's necromantic energy?). Poison will take effect once the spell wears off.
The spell can be ended by the caster at any time, but otherwise lasts for 1 turn + 1 round/level. I wonder, can the target get up at any point, or is he immobile until the spell ends? I was starting to think that this could be a very potent offensive spell, as it grants no saving throw, but then I noticed that it only works on willing recipients.
The material component is a pinch of graveyard dust.
Glyph of Warding: Another new spell. This one is used to protect an area from trespassers. The cleric inscribes a glyph that wards an area of 25 square feet per level. The glyph takes effect when touched or crossed, unless the name of the glyph is spoken first. A few sample glyphs are suggested: one that deals 2 points of electrical damage per caster level (seems a bit weak), another that deals fire damage, and ones that cause paralysis, blindness or energy drain. The last one is said to be available only to high-level clerics, but there's no concrete number given. (I expect this spell will be greatly expanded on in the Dungeon Master's Guide.)
If the warded area is over 50 square feet, the caster will need 2,000gp worth of powdered diamond. Otherwise all you need is a bit of incense.
Locate Object: Lets the caster know if the desired object is present, as long as he's facing it and it's within range. The object must be "known or familiar", which is a pretty vague restriction, and it also can't be a living creature.
The reverse of the spell, obscure object, protects an item from location by any spell.
Oddly, this spell was better explained in OD&D, where it says that specific items to be located (such as magic items) require knowledge of exact details such as colour and shape, while more general items like stairs can be located without such knowledge. The cleric version of the spell had a range of 9" + 1"/level in OD&D, but in AD&D it's been brought back in line with the magic-user version, and has a duration of 6" +1"/level.
Prayer: This is like the 2nd-level chant spell, in that it grants allies +1 to attacks and saving throws, while making enemies suffer -1 penalties. The difference is that it takes much less time to cast, and the cleric can take other actions while the spell is in effect. It's a far, far superior spell and makes chant almost completely worthless.
The OD&D version of prayer was a completely different spell: it lowered enemy saving throws by 1 point for every ten levels of the caster. The AD&D version seems much more useful.
Remove Curse: Removes any curse from a person, place or object. It doesn't destroy cursed weapons or armour, although it does allow a character affected by such an item to rid himself of it.
The reverse is bestow curse, which lasts for 1 turn/level, and will have one of the following effects: reduce an ability score to 3; afflict a -4 penalty to attack rolls and saving throws; or make the victim 50% likely to drop whatever he's holding (presumably this happens throughout the duration rather than just once, otherwise it's a super-weak curse). There's leeway given for clerics to devise their own curses as well, so long as they're of similar power.
The OD&D version of the spell was similar, but it was able to turn cursed weapons and armour back to normal. It also wasn't reversible.
Speak With the Dead: Allows the caster to ask questions of any dead creature, and receive answers according to that dead creature's knowledge. Higher level casters can ask more questions, and are able to successfully cast the spell on creatures that have been dead for longer. Clerics of level 21+ can question creatures that have been dead for 1,000 years, which sounds good, but could run into some language difficulties given that caster and target must be able to speak the same tongue.
The OD&D version of the spell was, as is usual, quite a bit simpler. The caster was able to ask three questions, regardless of caster level. Level was a factor in speaking with creatures dead for longer periods of time, though: clerics up to 7th level could talk to those dead for 1-4 days, those up to 14th level could speak to those dead for 1-4 months, and clerics over 20th level had no limit at all. AD&D uses a table to break these into smaller categories, and also limits it to 1,000 years maximum. The OD&D spell ends by suggesting that the dead creature answer in the form of a riddle, which AD&D dispenses with.