The reading is from St. Paul's Second Letter to the Corinthians 11:1-6

Brethren, I wish you would bear with me in a little foolishness. Do bear with me! I feel a divine jealousy for you, for I betrothed you to Christ to present you as a pure bride to her one husband. But I am afraid that as the serpent deceived Eve by his cunning, your thoughts will be led astray from a sincere and pure devotion to Christ. For if some one comes and preaches another Jesus than the one we preached, or if you receive a different spirit from the one you received, or if you accept a different gospel from the one you accepted, you submit to it readily enough. I think that I am not in the least inferior to these superlative apostles. Even if I am unskilled in speaking, I am not in knowledge; in every way we have made this plain to you in all things.