Leviticus Twenty-One - Priestly Regulations

"He who is the high priest among his brethren, on whose head the anointing oil was poured and who is consecrated to wear the garments, shall not uncover his head nor tear his clothes; nor shall he go near any dead body, nor defile himself for his father or his mother; nor shall he go out of the sanctuary, nor profane the sanctuary of his God; for the consecration of the anointing oil of his God is upon him: I am the Lord," Leviticus 21:10-12, NKJV. #PriestlyRegulations
God established specific regulations for those who served as priest in the temple during the previous dispensation and for those who served as overseers in the church age; most of the rules dealt with dress, grooming, public and private behavior and how to minister.
Ezekiel 44:10-31, 1 Timothy 3:1-7 and Hebrews 5:1-4.