These leadership groups were the political/religious leaders of the Jews in the days of Jesus. They are often referred to and the articles below will help you get a sense for each of the three groups as well as the Sanhedrin, the ruling council that was made up of each of these groups. All of them were threatened by Jesus and conspired together to have Him crucified.

Herodians [N] [S]
a Jewish political party who sympathized with ( Mark 3:6 ; 12:13 ; Matt, 22:16 ; Luke 20:20 ) the Herodian rulers in their general policy of government, and in the social customs which they introduced from Rome. They were at one with the Sadducees in holding the duty of submission to Rome, and of supporting the Herods on the throne. (Compare Mark 8:15 ; Matthew 16:6 .)

Sadducees [N] [B] [H] [S]
The origin of this Jewish sect cannot definitely be traced. It was probably the outcome of the influence of Grecian customs and philosophy during the period of Greek domination. The first time they are met with is in connection with John the Baptist's ministry. They came out to him when on the banks of the Jordan, and he said to them, "O generation of vipers, who hath warned you to flee from the wrath to come?" ( Matthew 3:7 .) The next time they are spoken of they are represented as coming to our Lord tempting him. He calls them "hypocrites" and "a wicked and adulterous generation" ( Matthew 16:1-4 ; 22:23 ). The only reference to them in the Gospels of ( Mark 12:18-27 ) and ( Luke 20:27-38 ) is their attempting to ridicule the doctrine of the resurrection, which they denied, as they also denied the existence of angels. They are never mentioned in John's Gospel.

There were many Sadducees among the "elders" of the Sanhedrin. They seem, indeed, to have been as numerous as the Pharisees ( Acts 23:6 ). They showed their hatred of Jesus in taking part in his condemnation ( Matthew 16:21 ; Matthew 26:1-3 Matthew 26:59 ; Mark 8:31 ; 15:1 ; Luke 9:22 ; 22:66 ). They endeavoured to prohibit the apostles from preaching the resurrection of Christ ( Acts 2:24 Acts 2:31 Acts 2:32 ; Acts 4:1 Acts 4:2 ; Acts 5:17 Acts 5:24-28 ). They were the deists or sceptics of that age. They do not appear as a separate sect after the destruction of Jerusalem.

Pharisees [N] [B] [H] [S]
separatists (Heb. persahin, from parash, "to separate"). They were probably the successors of the Assideans (i.e., the "pious"), a party that originated in the time of Antiochus Epiphanes in revolt against his heathenizing policy. The first mention of them is in a description by Josephus of the three sects or schools into which the Jews were divided (B.C. 145). The other two sects were the Essenes and the Sadducees. In the time of our Lord they were the popular party ( John 7:48 ). They were extremely accurate and minute in all matters appertaining to the law of Moses ( Matthew 9:14 ; 23:15 ; Luke 11:39 ; 18:12 ). Paul, when brought before the council of Jerusalem, professed himself a Pharisee ( Acts 23:6-8 ; Acts 26:4 Acts 26:5 ).

There was much that was sound in their creed, yet their system of religion was a form and nothing more. Theirs was a very lax morality ( Matthew 5:20 ; Matthew 15:4 Matthew 15:8 ; Matthew 23:3 Matthew 23:14 Matthew 23:23 Matthew 23:25 ; John 8:7 ). On the first notice of them in the New Testament ( Matthew 3:7 ), they are ranked by our Lord with the Sadducees as a "generation of vipers." They were noted for their self-righteousness and their pride ( Matthew 9:11 ; Luke 7:39 ; Luke 18:11 Luke 18:12 ). They were frequently rebuked by our Lord ( Matthew 12:39 ; 16:1-4 ).

From the very beginning of his ministry the Pharisees showed themselves bitter and persistent enemies of our Lord. They could not bear his doctrines, and they sought by every means to destroy his influence among the people.

Sanhedrim
More correctly Sanhedrin (Gr. synedrion), meaning "a sitting together," or a "council." This word (rendered "council," A.V.) is frequently used in the New Testament ( Matthew 5:22 ; 26:59 ; Mark 15:1 , etc.) to denote the supreme judicial and administrative council of the Jews, which, it is said, was first instituted by Moses, and was composed of seventy men ( Numbers 11:16 Numbers 11:17 ). But that seems to have been only a temporary arrangement which Moses made. This council is with greater probability supposed to have originated among the Jews when they were under the domination of the Syrian kings in the time of the Maccabees. The name is first employed by the Jewish historian Josephus. This "council" is referred to simply as the "chief priests and elders of the people" ( Matthew 26:3 Matthew 26:47 Matthew 26:57 Matthew 26:59 ; Matthew 27:1 Matthew 27:3 Matthew 27:12 Matthew 27:20 , etc.), before whom Christ was tried on the charge of claiming to be the Messiah. Peter and John were also brought before it for promulgating heresy ( Acts 4:1-23 ; 5:17-41 ); as was also Stephen on a charge of blasphemy ( 6:12-15 ), and Paul for violating a temple by-law ( 22:30 ; 23:1-10 ).

The Sanhedrin is said to have consisted of seventy-one members, the high priest being president. They were of three classes (1) the chief priests, or heads of the twenty-four priestly courses ( 1 Chronicles 24 ), (2) the scribes, and (3) the elders. As the highest court of judicature, "in all causes and over all persons, ecclesiastical and civil, supreme," its decrees were binding, not only on the Jews in Palestine, but on all Jews wherever scattered abroad. Its jurisdiction was greatly curtailed by Herod, and afterwards by the Romans. Its usual place of meeting was within the precincts of the temple, in the hall "Gazith," but it sometimes met also in the house of the high priest ( Matthew 26:3 ), who was assisted by two vice-presidents.

These dictionary topics are from
M.G. Easton M.A., D.D., Illustrated Bible Dictionary, Third Edition,
published by Thomas Nelson, 1897. Public Domain, copy freely.

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[N] indicates this entry was also found in Nave's Topical Bible
[S] indicates this entry was also found in Smith's Bible Dictionary
[H] indicates this entry was also found in Hitchcock's Bible Names
[S] indicates this entry was also found in Smith's Bible Dictionary

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Bibliography Information

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Bibliography Information
Easton, Matthew George. "Entry for Herodians". "Easton's Bible Dictionary". .