1 sn That is, they came down from Judea to Antioch in Syria.
2 tc Codex Bezae (D) and a few other witnesses have “and walk” here (i.e., instead of τῷ ἔθει τῷ Μωϋσέως [tw eqei tw Mwu>sew"] they read καὶ τῷ ἔθει τῷ Μωϋσέως περιπατῆτε [kai tw eqei tw Mwu>sew" peripathte]). This is a decidedly stronger focus on obedience to the Law. As well, D expands vv. 1-5 in various places with the overall effect of being “more sympathetic to the local tradition of the church at Jerusalem” while the Alexandrian witnesses are more sympathetic to Paul (TCGNT 377). Codex D is well known for having a significantly longer text in Acts, but modern scholarship is generally of the opinion that the text of D expands on the original wording of Acts, with a theological viewpoint that especially puts Peter in a more authoritarian light. The expansion in these five verses is in keeping with that motif even though Peter is not explicitly in view.
sn Unless you are circumcised. These teachers from Judea were teaching that Gentiles could not be saved unless they kept the law of Moses in regard to circumcision. Thus according to them a Gentile had first to become a proselyte to Judaism, including circumcision, before one could become a Christian. This party is sometimes known (collectively) as Judaizers. They did not question that Gentiles could come into the community, but disagreed with Paul and Barnabas on what basis they could do so.
3 tn Grk “Returning let us visit.” The participle ἐπιστρέψαντες (epistreyante") has been translated as a finite verb due to requirements of contemporary English style.
5 tn BDAG 422 s.v. ἔχω 10.b has “how they are” for this phrase.