Wall of Force
I Wall of Force that none shall pass.
This spell creates a 10 (ten) foot straight Line of protection which forbids creatures from crossing the barrier if active.
This spell may be raised and lowered by the casters command, by stating Wall up or Wall down. If the Wall of Force is active but down anything may pass, once up nothing may leave or enter including magic.
A Clearly Defined Line or area is one such as a Doorway, or an Edge to a front porch.
Special Note, it is highly recommended the caster mark the Area clearly, Safely, and properly. Outdoors on the grass powder such as chalking works well, and at night rope lights in a 10-foot straight line are an excellent marker.
Cutting into a wood Floor, or chalk on a deck are not good ideas for obvious reasons.