Bolts of Warding is a 7th level cleric Encounter power that was introduced in Divine Power.
Bolts of Warding
Cleric Attack 7
Your weapon crackles with divine lightning that arcs out to strike any who threaten your allies.
Melee weapon
Target: One creature
Attack: Strength vs. AC
Hit: 2[W] + Strength modifier lightning damage. Until the end of your next turn, any enemy takes 5 lightning damage if it ends its turn adacent to any ally within 5 squares of you