And they gave him audience unto this word, and [then] lifted up their voices, and said, Away with such a [fellow] from the earth: for it is not fit that he should live.
Note 13 at Ac 22:22: The Jews had put up with Paul recounting his experience where he came to recognize Jesus as the Christ, but they exploded again when he mentioned Jesus sending him to the Gentiles. This was the real issue.
The Jews had become more devoted to the rituals of their religion than they were to the God toward whom their religion was supposed to point them. They might possibly have accepted Jesus as the Christ if He would have left their religion alone, but He was constantly breaking their traditions (see note 8 at Mr 7:13 and note 9 at Mr 7:15).
One of the most dramatic and noticeable traditions of the Jews was the covenant of circumcision (see note 2 at Ac 15:1) and the concept that any non-circumcised person (Gentile) was totally separated from God (see note 3 at Lu 7:9 and note 3 at Ac 10:45). It infuriated the Jews to think that the Christians were presenting the Jewish Messiah to the Gentiles and telling them that they could become joint heirs with the Jews without becoming proselytes to Judaism through circumcision.