I made this mechanic, but I need some help with it. Please read through it and tell me what you think.

Prayer for Aid
Wounded and exhausted, a dwarf fighter looks out over the hill to see another wave of orcs charging towards her party. She clasps her hands in desperate prayer, asking Moradin to protect them, and when she looks up, each of her allies is wreathed in protective flame.

You can spend 1 minute in prayer, imploring your god for aid. The nature of the aid is determined by the domain your god is associated with. If your god is associated with multiple domains, you choose which prayer to use. Each friendly creature within 30 feet of you gains a benefit based on the prayer you invoke. When you use this feature, you can't use it again for 7 days.

Arcana
Prayer of Warding: For 10 minutes, when an effected creature takes damage from a magic weapon attack, spell, or other magical effect, the damage is reduced by an amount equal to half your level.

Forge
Prayer of Shielding: For 10 minutes, when an effected creature takes damage from an attack within 60 feet of them, they can use their reaction to reduce the damage taken by an amount equal to half your level and deal fire damage equal to half your level to their attacker.

Grave
Prayer of Resilience: If an effected creature is reduced to 0 hit points but not killed outright within the next 10 minutes, they drop to 1 hit point instead and the effect ends for them.

Life
Prayer of Health: For 10 minutes, each effected creature's hit point maximum increases by an amount equal to your level, and it gains the same number of hit points.

Light
Prayer of Radiance: For 10 minutes, when an effected creature damages a target with an attack or spell, they deal an extra d4 of radiant damage.

War
Prayer of Protection: For 10 minutes, each effected creature gains a number of temporary hit points equal to twice your level.

I need help thinking of effects for Nature, Tempest, and Knowledge and I need a name for this one.

Trickery
Prayer of ____: For 10 minutes, each effected creature becomes invisible. If they attack a creature or cast a spell, they become visible until the start of their next turn.

Please let me know what you think.

I love the idea behind this, though I'm curious how it's intended to be balanced in a campaign, is it just something you'd give to faithful players at a certain level, as a quest reward or such?

Without knowing when it's intended to be given it makes it hard to decide if any of the effects are over or under powered.

Otherwise the only one that jumps out at me right away is Prayer of Shielding, which is conspicuous in that it has no element based on your level; it would probably be reasonable to make its damage reduction and damage half your level as per Prayer of Warding? The Shielding prayer can apply to any damage, but it's limited by reaction (has to inflict damage, can only trigger once per turn) whereas Prayer of Warding could reduce damage for multiple attacks per turn depending upon the situation, so I think they remain balanced against each other. You might also consider a range on the Shielding damage, for example 60 feet (in line with Hellish Rebuke).

For the Trickery prayer, how about Prayer of Concealing/Concealment? Regarding the effect, like Shielding it has no tie to player level, what if the invisibility doesn't trigger right away, but instead the affected creature can trigger when they want to, at which point it lasts up to a number of rounds equal to your level (but still ends early if you attack/cast etc.)?

Wow, thanks for the feedback, I love these ideas! The 1d6 was kind of a relic to when I wanted this to be a cleric exclusive thing, before i realized it would be cool to have all classes be able to use these, and I kept it because I didn't know what to replace it with.

In response to your question of what level it would be given at, I'd say around level 10 as a reward for a quest that their god send them on, or give it to them if they pray to their god in a "darkest hour" type of situation, like the flavor text about the dwarf.

Also, how do you think the Trickery Domain should be worded? I don't want to confuse players.

I also need effects for the Nature, Tempest, and Knowledge domains, do you guys have any ideas?

For the Trickery prayer I'd word it something like:

Prayer of Concealing

Once during the next 10 minutes, each affected creature can use their bonus action to become invisible. Once triggered, this invisibility lasts a number of rounds equal to half your character level (rounded up) or until the creature attacks or casts a spell.

This is still potentially quite a potent ability, but isn't competing as much with a full-blown Invisibility spell.

As for other prayers… the simple option for Tempest would be to make it much the same as Shielding but with lightning instead of fire, I haven't thought of anything more unique that I like yet.

For Nature I was wondering about some kind of restraining mechanic, for example each creature would gain a bonus action which they can use to attempt to entangle one enemy within range (quite short, like 10 or 15 feet?), target must pass a Dexterity or Strength save equal to 8 + half your character level, and on failure they are Restrained until the end of their turn. Basically can give a group a shared crowd control ability that they can coordinate to lock down multiple opponents. Not sure about the DC, don't want it to be too high in case the group are all using it over and over again.

Haven't had any ideas for the others so far.

For Concealing, do they use their action, bonus action, or reaction? Also, I like the idea of a reactionary knockback for Tempest with thunder or lightning damage.

Oh whoops, forgot about that, I've tweaked it to bonus action on the assumption that it's limited enough in time you want to hold off until you really need it to use it, so probably in the midst of a combat. A Tempest knockback could be cool, it could maybe do a fixed roll for damage, but use the kind of DC mechanism I used in my Nature idea (8 + half level) so the pushback gets harder to resist?

How far should the knockback be?

If the damage is low (d6?) then 10 feet is the standard for effects like Thunderwave, charge attacks etc. Otherwise if you'd prefer to deal a bit more damage 5 feet is the minimum you need to push something to avoid attacks of opportunity, this is how far a shove will send someone.

Ok, I'll make it 5 feet with half your level in thunder or lightning, your choice. What should it be called?

I still need ideas for the Nature and Knowledge domains, anyone else have ideas?

Anyone?

Any other ideas?

I know this isn't the same thing, but this reminds me of the Oblations I wrote up a while back. Essentially every god in the setting's pantheon had an activity related to them the a character could perform, and doing so would reward them with Inspiration. Each activity required role play through some kind of related scene, designed to inspire interesting rp and further the interest of the specific god. 

Perhaps Nature requires a restorative environmental act? Curing a blighted tree, purifying a river or planting a grove? 

Knowledge might require a secret to be retrieved and made public. Or perhaps acting as a tutor to a group of children? Research of some kind? 

Those are cool ways to get quests from your god, but I need ideas for the ability itself, not how to get it as a reward. I need ideas for the Nature and Knowledge domains.

Nature might yield a healing fruit from a nearby plant, or remove an illness. Knowledge might grant a reroll on a knowledge-based skillcheck, or reveal an important fact that is currently relevant.

I like the Knowledge one, not a fan of the Nature one though.

Anyone else?

Any ideas for the Nature Domain?

Anybody?