Spiritual warfare is the Christian version of the concept of taking a stand against preternatural evil forces. The foundation for this ideology is having a belief in evil spirits which are able to intervene in human affairs. Various Christian groups have adopted practices to repel such forces, as based on their doctrine of Christian demonology. Prayer is a common form of spiritual warfare among Christians. Other practices may include exorcisms, laying-on of hands, fasting, or anointing with oil.