Cannot be affected by Divine Shield, Hand of Protection or Lay on Hands.
Duration: 30 seconds
Empowered by the Light, paladins can surround themselves with an impenetrable barrier of positive energy. While they are encased in it, physical and magical attacks cannot do them any harm.
Divine Shield is a level 10 paladin spell that prevents all damage to the paladin for a short period of time. Divine Shield also protects the paladin from all unfriendly spells (except [Mass Dispel]), acts as a universal "cleanse" removing nearly all debuffs, and can be cast even while affected by most crowd control effects ([Polymorph], [Fear], etc). Using Divine Shield also causes [Forbearance], preventing the paladin from being affected by Divine Shield, [Hand of Protection] or [Lay on Hands] for 30 seconds.
Divine Shield cancels virtually all crowd control effects, including a [Silence] from another player. The exception is when casting has been interrupted by a spell lock effect such as Mage's [Counterspell], Rogue's [Kick], Warlock Felhunter's [Spell Lock] or Death Knight's [Mind Freeze]. This will lock out all spells that derive their power from the same school of magic as the spell that was interrupted.
Divine Shield cannot be cast under the effect of [Cyclone] and similar effects.
Divine Shield prevents all damage, including (unlike most other bubbles of other classes) falling damage, and even drowning damage. It is not uncommon for a paladin to leap off a high cliff or despawn their flying mount in the air and bubble before landing, preventing damage or death. [Hand of Protection] does exactly the same thing for falling damage, and a paladin with good timing may bubble himself and a party member.
In the Arathi Basin battleground, you cannot use Divine Shield and then attempt to capture a node, otherwise known as a flag or base. Similarly, when you capture a flag in Eye of the Storm or Warsong Gulch, the use of Divine Shield will cause you to automatically drop the flag. You cannot continue to carry it while under the spell of Divine Shield.
Divine Shield does not wipe threat, but mobs will ignore targets under the influence of Divine Shield unless there is no other valid target for them, which can lead to death of raid/party members if used in the wrong situation. On the other hand, if a paladin healer or DPS pulls aggro, they can use Divine Shield to make the mobs ignore them.
It sometimes is helpful if a tanking paladin activates the shield and then immediately remove the Divine Shield again (best through a macro) to instantly remove all harmful spells. A good paladin should have a taunt immediately ready for such a case (often referred to as a "bubble-taunt"). This is best done through a macro (/cancelaura Divine Shield) followed on the next line by (/cast Hand of Reckoning).
Holy and Retribution paladins can use Divine Shield to avoid being killed when casting [Hand of Sacrifice] on a tank about to take an extremely high amount of damage.
When fighting alone against a mob that uses primarily a ranged attack, Divine Shield will cause the mob to run up to melee. Combined with another ranged attack, such as [Avenger's Shield] or [Exorcism], this can be used to solo pull a mob in a somewhat crowded area (if you hit only one mob with the shield, that is).
Divine Shield originally appeared in Warcraft III: Reign of Chaos and was used by the Paladin hero unit. The highest level divine shield in allowed for 45 seconds of immunity every 65 seconds with no attack speed penalty and disallowed any units from attacking it. It is also worth noting that the Warcraft III version could not be dispelled, whereas the World of Warcraft version can.