Blessing of Wisdom

Talent improvements
Improved Blessing of Wisdom (Holy Talent): Increases the effect of your Blessing of Wisdom spell by 10% per rank (2 ranks total).

With both ranks trained, Rank 9 of the Blessing of Wisdom will be 109-110 mana per 5 seconds.

Greater Blessing of Wisdom
Paladins also have Greater Blessings, which includes a Greater Blessing of Wisdom which can be learned from the class trainer. Each Greater Blessing affects all players of the targeted class within your party or raid and lasts for 30 minutes.

Each Greater Blessing you cast requires the reagent Symbol of Kings which can be bought at any reagent vendor.

Tips and tactics
Blessing of Wisdom is most often given to a healer, but also to other mana using classes such as Mages, Warlocks and Hunters.

Cataclysm changes
In Cataclysm, Blessing of Wisdom and Blessing of Might were combined, increasing attack power by 10% and granting a various amount of mana regeneration.

Trivia

 * Blessing of Wisdom is a common Paladin spell in Hearthstone. The flavor text reads: "Apparently with wisdom comes the knowledge that you should probably be attacking every turn."