hong said:Er, that's the point. You cast this Word of Protection thing on the monster's turn, ideally after it's rolled its attack but before it rolls damage. Or, if the DM is being a hardass, you cast after it declares its attack, but before the attack roll. Either way, it acts to prevent damage from being dealt, which is, if anything, better than healing afterwards.
Ok, then probably power description should be something like
Immediate Reaction
Trigger: Enemy is attacking (has hit) your ally within N squares of you.
Effect: Target gains resistance all 5 till end of the attack (or next turn?)
If you make it once per encounter, seems reasonably balanced. At-will is probably an overkill.