John Gill Commentary Acts 22:19

"And I said, Lord, they themselves know that I imprisoned and beat in every synagogue them that believed on thee:" — Acts 22:19 (ASV)

And I said, Lord, they know, that I imprisoned
Men and women, that made a profession of the Christian religion, (Acts 8:3)

and beat in every synagogue them that believed on thee ;
in Jerusalem there were many synagogues, and in these scourging and beating of offenders were used; (See Gill on Matthew 10:17).