Tome of Fiery Redemption

Tome of Fiery Redemption is an epic trinket for paladins.

It represents a significant threat boost for protection paladins, as - in addition to the casting of spells - it will proc from Consecration ticks, Judgment refreshes, and mana/health gains from Seal of Light. This means that paladins will receive the spell damage bonus almost immediately at the beginning of a fight. It has a 15% proc chance, a 45 second hidden cooldown and lasts 15 seconds.

Source
This item drops from Al'ar in the Eye.