Why Were the Jews Trying to Kill Paul?

Act 23:12 And when it was day, the Jews banded together, and bound themselves under a curse, saying that they would neither eat nor drink till they had killed Paul.
Act 23:13 And they were more than forty that made this conspiracy.
Act 23:14 And they came to the chief priests and the elders, and said, We have bound ourselves under a great curse, to taste nothing until we have killed Paul.
Act 23:15 Now therefore do ye with the council signify to the chief captain that he bring him down unto you, as though ye would judge of his case more exactly: and we, before he comes near, are ready to slay him.

Was Paul's teaching a threat to the Jews?