You have heard, no doubt, of my earlier life in Judaism. I was violently persecuting the church of God and was trying to destroy it. I advanced in Judaism beyond many among my people of the same age, for I was far more zealous for the traditions of my ancestors. But when God, who had set me apart before I was born and called me through his grace, was pleased to reveal his Son to me, so that I might proclaim him among the Gentiles, I did not confer with any human being, nor did I go up to Jerusalem to those who were already apostles before me, but I went away at once into Arabia, and afterwards I returned to Damascus.
Then after three years I did go up to Jerusalem to visit Cephas and stayed with him fifteen days; but I did not see any other apostle except James the Lord’s brother. In what I am writing to you, before God, I do not lie! Then I went into the regions of Syria and Cilicia, and I was still unknown by sight to the churches of Judea that are in Christ; they only heard it said, “The one who formerly was persecuting us is now proclaiming the faith he once tried to destroy.” And they glorified God because of me.
Galatians 1:13-24 (NRSV)