Question: "What were the chief priests?"
Answer: The office of chief priest was a high position among the Israelites. In the Old Testament, the terms chief priest and high priest are sometimes alternate translations of the same Hebrew phrase (compare 2 Chronicles 26:20 in the NIV and NET). In Jesus’ day the office of chief priest seems to have been distinguished from that of the high priest. Mark 14:53 lists several groups of people involved in Jesus’ arrest: “They took Jesus to the high priest, and all the chief priests, the elders and the teachers of the law came together.” These chief priests mentioned by Mark were high-ranking members of the priesthood who served on the Sanhedrin. A chief priest is named in Acts 19:14: Sceva.
The priesthood was instituted by God after the children of Israel left Egypt during the Exodus. In Numbers 3:12–13 the Lord set apart the entire tribe of Levi for special service. From the Levites came the priests, and among the priests were the high priest and, in Luke 19:47, the “chief priests.”
The chief priests would have been from the tribe of Levi. Moses, Aaron, and Miriam were all Levites, as were thousands of other men and women. God indicated that the high priest had to be a direct descendant of Aaron. All priests were Levites, but not all Levites were priests. Only some of the Levites belonged to the Aaronic priesthood. Exodus 29:7–9 states, “Take the anointing oil and anoint [Aaron] by pouring it on his head. Bring his sons and dress them in tunics and fasten caps on them. Then tie sashes on Aaron and his sons. The priesthood is theirs by a lasting ordinance. Then you shall ordain Aaron and his sons.” Only the high priest, or chief priest, could enter the Most Holy Place once a year on the Day of Atonement (Yom Kippur). The other Aaronic priests served in rotating “courses” so that they could have a turn to minister in the Holy Place and offer sacrifices (see Luke 1:8–9).
The other Levites (not descended from Aaron) served in other ways. The other sons of Levi were involved in carrying the ark and the various parts of the tabernacle. After the temple was built, the Levites were involved in caring for the temple. Numbers 3 provides information about them.
Acts 23 demonstrates that the priesthood was not functioning as outlined in the Pentateuch. The Sanhedrin, for example, was not a Mosaic concept, and neither was the idea of many “chief priests.” The Sanhedrin was probably begun about 70 BC by Alexander Janneaus, the Hasmonean king of Judea. Eventually, the Sanhedrin consisted of 70 or 71 elders and scholars, including the high priest (usually the president of the body), other Levitical priests, Sadducees, and Pharisees. The purpose of the Sanhedrin was to act as a tribunal in making decisions regarding the Law.
In Acts 23:2 Paul is on trial. Ananias is identified as the high priest in charge of the proceedings. Then, verse 14 mentions “the chief priests and the elders.” The “chief priests” were probably Sadducees and others in the Sanhedrin. Both the NIV and NASB refer to “chief priests” in the plural. Other translations call them “leading priests” (NLT) or “princes of the priests” (Jubilee Bible 2000). The chief priests probably included Ananias and other priests who wielded a certain amount of political power and influence.