From wow.incgamers.com

Statistics

Talent Improvements

Holy Tree

Talent: Divine Illumination Talent
Effect: Reduces the mana cost of all spells by 50% for 15 sec.
Statistics: N/A.

Protection Tree

None.

Retribution Tree

None.

Threat Level

This skill generates Moderate Threat.

Uses in PvP

• Can only be used outside of combat, but can be used in all types of PvP.

Uses in PvE

• Can only be used outside of combat, but can recover a Party or Raid if the Paladin have a Soulstone, is ressurected by a Druid, or if another Paladin casts Divine Intervention on you.

Other Facts

• The first skill rank is gained from the Gaining Redemption questline.
• There is no reason to avoid buying higher spell ranks.
• There is no reason to downrank your Redeption casts, as they all have same Mana cost, they just give the ressurected player more Hit Points and Mana.