No matter how your enemy maneuvers, something comes between it and its quarry—and that something is you.

Encounter   ✦     Martial, Weapon
Standard Action      Melee weapon

Target: One creature

Attack: Strength vs. AC

Hit: 3[W] + Strength modifier damage.

Effect: Choose one ally within 5 squares of you. The target cannot attack that ally with melee or ranged attacks until the end of your next turn.

Published in Player's Handbook, page(s) 149, Class Compendium.