Acts 15:1

"Some men came down from Judea and began teaching the brethren": That is, they came down to Antioch and tried teaching the following among the Christians there. Paul will later write that what such men were teaching was another gospel,. distortion of the true (Galatians 1:6), and were false brethren (Acts 2:4). They also claimed to have been sent by the apostles in Jerusalem (Acts 15:24). "Began": The verb tense is imperfect, and suggests continual efforts to force their false doctrine on the brethren in Antioch. "Unless you are circumcised according to the custom of Moses": They were also teaching that one must adhere to the Law of Moses as well (Acts 15:5). From this verse it is clear that Paul and Barnabas were not teaching that Gentiles had to be circumcised. Notice that these false teachers were appealing to Moses as the final authority, not Christ. Likewise modern Seventh Day Adventists claim that the Sabbath is an eternal law they may have argued that circumcision was part of an eternal covenant (Genesis 17:3). "But remember that the word "everlasting' must be understood in the light of whatever limitations are placed on it by its context" (Reese p. 528). "You cannot be saved": The conversion of Cornelius had taken place about 10 years prior, and still the apostles were basically battling the same issue. It is clear from the above statement that such false brethren were teaching that Christians from any ethnic battleground had to keep the Law of Moses to be saved. Compare with Galatians 5:1.