The reading is from St. Paul's Letter to the Galatians 1:1-3, 20-24; 2:1-5

Paul, an apostle - not from men nor through men, but through Jesus Christ and God the Father, who raised him from the dead - and all the brethren who are with me,

To the churches of Galatia: Grace to you and peace from God the Father and our Lord Jesus Christ.

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 not known by sight to the churches of Christ in Judea; they only heard it said, "He who once persecuted us is now preaching the faith he once tried to destroy." And they glorified God because of me. Then after fourteen years I went up again to Jerusalem with Barnabas, taking Titus along with me. I went up by revelation; and I laid before them (but privately before those who were of repute) the gospel which I preach among the Gentiles, lest somehow I should be running or had run in vain. But even Titus, who was with me, was not compelled to be circumcised, though he was a Greek. But because of false brethren secretly brought in, who slipped in to spy out our freedom which we have in Christ Jesus, that they might bring us into bondage - to them we did not yield submission even for a moment, that the truth of the gospel might be preserved for you.