Divine Defense

Choose up to 5 willing creatures within range. Each creature is protected by a spectral, radiant armor conjured by the power of the divines. For the duration, affected creatures have a +2 bonus to AC. Additionally, choose Radiant or Necrotic. The armor grants resistance to that damage to the chosen damage type. Further, when an affected creature is hit by another creature with a melee attack, the attacker takes 2d4 damage of the chosen type.

At higher Levels.  When you cast this spell using a spell slot of 7th level or higher, you can target one additional creature for each slot level above 6th. Additionally, the damage dealt by the armor increases by 1d4 for each slot level above 6th.