Line of protection

Line of protection was a cooperative abjuration spell that formed a field of force between two or more priests, or two or more stationary objects, that harmed all creatures passing through it, particularly evil and undead creatures. The reverse of this spell, line of destruction, was particularly painful to paladins and good-aligned creatures.

Effects
Two or more priests were required to cast this spell and had to decide during casting if the effect would be stationary or movable. If stationary, each priest drew a magical sigil on facing surfaces; opposite walls, two tree trunks, or facing supports of an arch or portcullis, for example. If the effect was to be mobile, then each priest became an endpoint (or an intermediate point, like a fence post) of the field of force. The distance between two adjacent sigils or priests was a maximum of, and once cast, could not be shortened or lengthened, forming a piecewise linear barrier.

The shimmering, translucent field of force extended from the ground to a height of 10 ft (3.1 m) and made objects on the other side hazy and indistinct. Any creature that passed through the field had to overcome the magic of the spell or suffer a small amount of damage. The line of protection was more than doubly effective on evil creatures and the undead. Creatures could fly over, burrow under, go around, or even teleport through the barrier with no ill effect.

If cast to be a movable barrier, the priests could move at half their normal rate and were forced to maintain the same distance apart as set at casting time. The field could not be bent and if any object greater than in diameter blocked the line of sight between two adjacent priests, the spell was immediately broken.

When cast in reverse, line of destruction functioned the same as above except paladins and good-aligned creatures took extra damage.

Components
In addition to verbal and somatic components, the priests casting the mobile version of this spell had to hold their staves, croziers, or religious standards vertically, forming an anchor or corner of the force field.