Underlying the priesthood is belief in a supreme High God to whom humans must give an accounting, especially for the shedding of blood. The ancient laws and received traditions governing priestly ceremonies, sacrifices, cleansing and healing rituals clarify the role of the priest as one who offers sacrifice for the people according to sacred law.
Shamans can be found among many populations around the world: Africa, Asia, Australia, and the Americas. They tend to serve small tribal communities or nomadic clans, whereas priests historically serve at shrines and temples under the authority of high kings and rulers. Another difference is the gender-transgressive (cross-dressing, transvestite) practice that occurs with shamanism. However, transvestism was prohibited among the Hebrew ruler-priest caste, the oldest known order of priests.