Devotion's Rebuke

Blood from the attacked bolsters the blade of the paladin and glows with holy light.  The paladin makes a weapon attack.

In addition, the target takes 2d6 radiant damage and makes a constitution saving throw. (the dc being how much damage they dealt in the attack that triggered the reaction). If they fail the constitution saving throw,  the target becomes charmed to their original target until attacked by the original target. 

Per spell level above 2nd level the d6 radiant damage is increased by 1. (3rd level = 3d6)