Aura of protection or Destruction

When you cast this spell, you radiate an otherworldly
energy that warps the fate of all creatures within 30 (Radius) feet
of you. Decide whether to call upon either a celestial or a
fiend for aid. Choosing a celestial charges a 30-foot-radius
around you with an aura of nonviolence; until the start
of your next turn, every attack roll made by or against a
creature inside the aura is treated as a natural 1. Choosing
a fiend charges the area with an aura of violence; until the
start of your next turn, every attack roll made by or against
a creature inside the aura, including you, is treated as a
natural 20.
At Higher Levels. When you cast this spell using a spell
slot of 4th level or higher, you can extend the duration by
1 round for each slot level above 3rd.