John Calvin Commentary Acts 14:2

"But the Jews that were disobedient stirred up the souls of the Gentiles, and made them evil affected against the brethren." — Acts 14:2 (ASV)

And those Jews which believed not, indeed, they are persecuted anew, and this by the Jews, for they were like firebrands to inflame the minds of the Gentiles. For it is to be supposed that the Gentiles would have tolerated hearing the gospel preached, unless they had been incensed by these instigators to resist.

I interpret κακωσαι here to mean resisting with malicious intent, or to inflict harm.

Under the name "brethren," Luke includes, in my judgment, all the godly; namely, that whoever embraced the gospel was vexed and troubled, as if some pernicious sect had risen to spread discord, to trouble the peace of the city, and to shake the public state. Yet, if anyone prefers to limit its meaning to Paul and Barnabas, I do not strongly object.