Acts.13.43  And when the meeting of the synagogue broke up, many Jews and devout converts to Judaism followed Paul and Barnabas, who spoke to them and urged them to continue in the grace of God.
Gal.1.13  For you have heard of my former life in Judaism, how I persecuted the church of God violently and tried to destroy it;
Gal.1.14  and I advanced in Judaism beyond many of my own age among my people, so extremely zealous was I for the traditions of my fathers.

Hyper-concordance v1.1, by Sean Boisen. Scripture verses taken from the Revised Standard Version, copyright 1952, 1971.