This is for all pallys that aren't tanking for Sarth +3:
You must be speced for Divine Guardian. The damage reduction for from bubble is there to help mitigate the damage done while Shadron and Vesperon are both up. If we can coordinate correctly, we should be able to get about 36 secs of reduced damage with those two up. This would go a long way towards not letting the dps kill themselves with reflective damage.
If you come to raid without being speced for it, you will be giving a port to IF to respec or replaced.