“And when it was day, certain of the Jews banded together, and bound themselves under a curse, saying that they would neither eat nor drink till they had killed Paul.”
King James Version (KJV)
23:12 Some of the Jews bound themselves - Such execrable vows were not uncommon among the Jews. And if they were prevented from accomplishing what they had vowed, it was an easy matter to obtain absolution from their rabbis.
Ac 23:12-15 Certain of the Jews banded together. Perhaps these Jews were of the bitter enemies from Asia who had laid hands on him in the temple. They may have belonged to a wild fanatical association of Jewish assassins, who, a few years later, played a prominent part, called Sicarii. The Talmud says that those who took such a vow were released from it, if it was impossible to carry it out. Their purpose was to induce the chief priests, who were Sadducees, to have Paul appear before the Sanhedrin the next day, and then they would murder him.