Theme: Jesus Christ has cleansed all those who trust in him; don't add new burdens on your brother

At the time in which Galatians was written, Antioch was the 3rd largest city of the Roman Empire with a population of nearly 250,000 and maybe 25,000 Jews.

Do not admit a charge against an elder except on the evidence of two or three witnesses. As for those who persist in sin, rebuke them in the presence of all, so that the rest may stand in fear. - 1 Timothy 5:19-20

We have heard that some went out from us without our authorization and disturbed you, troubling your minds by what they said. - Acts 15:34

Old Covenant Purity Laws
After the LORD has given instruction about the sacrifices needed to come into his presence and meet with him (Leviticus 1-9), two Israelite men, Nadab and Abihu, offer ‘unauthorised fire’ before the LORD (Leviticus 10:1). They are sincere in their desire to worship the LORD, but they decide to do so in a way that he has not commanded. As a result, they are killed with fire and the tabernacle becomes unclean. The LORD then gives new laws to explain how the tabernacle and people are to be cleansed so that God will remain in their midst without them being destroyed by his presence. The clean/unclean laws (Leviticus 11-16) are not about atoning for sin, but dealing with the pollution that comes from sin and living in a fallen world. - M Morales, Who Shall Ascend the Mountain of the LORD?