Before he came to Christ, Paul violently persecuted the Church. In Galatians 1 Paul shares that God broke into his life in an apocalyptic and lifechanging event. He was no longer zealously persecuting the Church, but zealously preaching the Gospel. He adds that what he preaches is not man's gospel, that we can add anything to our salvation, but it is Christ's saving work on the Cross, and nothing more by which we are saved.