Born For Freedom
Abraham had two children, Isaac and Ishmael. Those children were from different mothers, Isaac was from Sarah, Abraham's wife, and Ishmael was from Hagar a slave woman. The slave woman with her child was eventually sent away while the son of Sarah was prized and kept. Afterward the descendants of Ishmael continually persecuted the descendants of Isaac. Paul in Galatians made that into a rule that said slave children are always jealous and angry with free children.
28 And you brethren, like Isaac, are children of promise.
29 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 also.
30 But what does the Scripture say? "Cast out the bondwoman and her son, for the son of the bondwoman shall not be an heir with the son of the free woman."
31 So then, brethren, we are not children of a bondwoman, but of the free woman—(Gal 4:28-31).
The point is that we should expect persecution from Christians with a slave mentality, who are slave to rules, as opposed to the free children who embrace the ministry of the Holy Spirit. We are to make sure that we don't have a slave mentality but a free mentality that exalts the grace of God and fulfills the rules through the Holy Spirit.