Sosthenes in Fausset's Bible Dictionary

A Jew, "ruler of the synagogue," after Crispus on conversion had ceased to be so. Probably ringleader of the spiteful Jews who with one accord made insurrection against Paul, and brought him to Gallio's judgment seat. When Gallio would not be made the tool of their spite, but drove them from his judgment seat, the Greeks or Gentiles, seeing the deputy's feeling which they sympathized with, against the Jewish bigots, seized Sosthenes and beat him before Gallio's judgment seat; and Gallio cared for none of these things, i.e. refused to interfere, being secretly pleased that the mob should second his own contempt for the fanatical Jews. But in 1 Corinthians 1:1 we find Sosthenes under very different circumstances, no longer against Paul, but associated with him in saluting the Corinthian Christians. Whence arose the change? Paul probably showed Christian sympathy for an adversary in distress; the issue was the conversion of Sosthenes. Saul the persecutor turned into Paul the apostle, and Sosthenes the ringleader of persecution against the apostle, were two trophies of grace that, side by side, would appeal with double power to the church at Corinth. Paul designates "our brother" in a way implying that Sosthenes was well known to the Corinthians, though at the time of writing he must have been with Paul at Ephesus.