Sanctity Aura

Sanctity Aura is a passive Retribution paladin ability, available at level 80. It increases Versatility by 3%.

History
Sanctity Aura was a talent in the Retribution tree that increased Holy damage done by 10%. You needed to spend 21 points in Retribution to learn it. It was a staple of the Retribution specialization due to the offensive, DPS nature of the spec. Its presence typically indicated that the paladin was primarily oriented towards dealing damage and enhancing his party's as well, becoming something of a "combat buffer". This was removed from the game in Patch 3.0.2.

It was re-added in Patch 6.0.2 as a passive ability, granting 3% Versatility instead.

Talent improvement
Improved Sanctity Aura increased damage of anyone affected by the aura by 1%/2%. This included physical as well as Holy damage. This was a base change to melee damage and an end-damage amplification to spells. (Note: Prior to Patch 2.1.0 this instead gave a 3%/6% bonus to healing done to party members.)

Tips and tactics
Sanctity Aura was, for obvious reasons, the ret-spec aura and part of what separated ret pallies from the other specs. With the Improved Sanctity Aura talent, it benefited all other damage-dealing classes as well.

Sanctity Aura was very useful for shockadins (40/0/21 build), because it increased their Holy Shock and Seal of Righteousness damage by 10%. Smite Priests loved this aura because it provided a flat 10% increase to their DPS.

Paladin tanks also liked Sanctity Aura in their group, as it helped their threat generation enormously.