The reading is from St. Paul's Letter to the Galatians 4:28-31; 5:1-10

Brethren, we, like Isaac, are children of promise. But as at that time he who was born according to the flesh persecuted him who was born according to the Spirit, so it is now. But what does the scripture say? "Cast out the slave and her son; for the son of the slave shall not inherit with the son of the free woman." So, brethren, we are not children of the slave but of the free woman. For freedom Christ has set us free; stand fast therefore, and do not submit again to a yoke of slavery. Now I, Paul, say to you that if you receive circumcision, Christ will be of no advantage to you. I testify again to every man who receives circumcision that he is bound to keep the whole law. You are severed from Christ, you who would be justified by the law; you have fallen away from grace. For through the Spirit, by faith, we wait for the hope of righteousness. For in Christ Jesus neither circumcision nor uncircumcision is of any avail, but faith working through love. You were running well; who hindered you from obeying the truth? This persuasion is not from him who calls you. A little leaven leavens the whole lump. I have confidence in the Lord that you will take no other view than mine; and he who is troubling you will bear his judgment, whoever he is.