The area of effect for this spell was a 10 ft (3.1 m) cube per level of the caster. These cubes could be used to form any desired rectangular shape. The barrier of retention did no harm to those inside or entering the protected area, but prevented them from leaving unless they could resist the spell. This spell also prevented physical attacks (melee attacks, ranged weapons, hurled objects) from exiting the area. The barrier did not prevent magical attacks from leaving the area, nor any spellcasting within the area, so magic missile could hit targets outside the barrier and teleport could be used to escape it. Dispel magic and similar disenchantments could cancel the barrier. The caster was free to enter and leave the protected area at will.
This spell required a verbal component. For the somatic component, the priest had to walk the perimeter of the desired area while casting the spell. The material component was a small cage made of silver wire.