Acts 21:24
Them take, and purify thyself with them, and be at charges with them, that they may shave their heads: and all may know that those things, whereof they were informed concerning thee, are nothing; but that thou thyself also walkest orderly, and keepest the law.
The counsel was that Paul should take four men who were under a vow, purify himself together with them, and pay their expenses so that they could shave their heads and thus complete the vow. The four were Christian believers in Jerusalem under the Nazarite vow whose term was nearly expired. To finish it still required costly sacrifices for purification that a very poor man could not afford, and it was regarded as a pious act for a wealthier man to defray another's cost. Paul himself was poor and supported himself by his own labor, yet he paid the cost and accompanied them into the temple to unite with them in the seven days of purification ceremonies. In this way he agreed to and complied with the counsel, joining the men in purification and paying their expenses.
The public act was meant to give a decisive contradiction of the false reports and to remove misapprehension. It was to show all that the reports that Paul taught the Jews living among the Gentiles to forsake Moses, to abandon circumcision of their children and Jewish customs, were empty. It was to show that Paul himself lived in an orderly manner and kept the law. At the same time the leaders indicated that the ruling concerning Gentile believers remained unchanged: they were not bound by the ceremonial law but were to observe only abstinence from things offered to idols, from blood, from things strangled, and from fornication.
In giving this counsel the elders placed the whole burden on Paul instead of defending him and correcting the disaffected party, treating him as responsible for the existing prejudice as though he had caused it. The counsel was not prompted by the Spirit but was a compromise born of cowardice. It was inconsistent with the leaders' own former decision about Gentile converts and the ceremonial law, a decision sanctioned by the Holy Spirit. It was driven by fear that failure to conform to the ceremonial law would bring the hatred of unbelieving Jews and expose Christians to severe persecution. The Sanhedrin was doing its utmost to hinder the gospel by sending men to follow the apostles, especially Paul, to oppose them, and condemnation before the Sanhedrin as breakers of the law and apostates from the Jewish faith would bring swift and severe punishment.