Fanaticism is one of the most potent Offensive Auras the Paladin has in his arsenal. Compared to his other two physical augmentation auras, Might and Concentration, it has a greater damage bonus, and on top of that also increases his attack rating and attack speed, which makes this aura the best of the three for single play. The one drawback is in party play: it provides less damage boost to your allies, and has a shorter range than it's two predecessors.
True faith can cause its believers to perform fantastic feats. With this aura the Paladin, and all those allied with his cause, carry themselves with a zealous fervor, allowing them to strike down their foes as swiftly as the scythe reaps the harvest.
↑Diablo II Manual, page 82. Blizzard Entertainment, 2000.