Increases the effectiveness of your healing spells by X%, and critical hits made against you have a X% chance to prevent you from being critically hit again for 6 sec.
Blessed Resilience is a holy priest talent with a maximum of 3 ranks. It gives the priest a chance of 20% per skill point spent from being critically struck by attackers after being critically hit once. It also increases the effectiveness of healing spells by 1% per skill point spent.
This talent is interesting both for pvp and pve talent specializations. For pvp this is a no-brainer. While the buff "Blessed Resilience" is active, it is impossible for you to be critically hit, which greatly increases you chances to survive if your are attacked by a class that relies on critical hits for damage. The buff overrides the 100% crit effects of a rogue's Cold Blood and a warrior's Recklessness. However, since the talent is quite deep down in the holy-tree, any pvp healing priest would have to forego Penance and Pain Suppression, which would be unacceptable.
However, Blessed Resilience also increases all you healing done by 1% per skill rang. This alone makes it an interesting talent for PvE-healing. Of course, it is not as good as Spiritual Healing, which increases all healing done by 2% per skill rank, but depending on your play style it might be better than Empowered Healing or Divine Providence.
Patch 3.2.0 (04-Aug-2009): Now properly triggered by periodic critical strikes.