What does Acts 16:1 mean?
Paul and Barnabas received confirmation from the church leadership in Jerusalem that Jesus-followers do not have to be circumcised or adhere to the Mosaic law (Acts 15:22–29). The two had intended to take this message to the Gentile churches they'd planted in modern-day Asia Minor. An argument over whether they should take Barnabas' cousin John Mark split the pair. Barnabas takes Mark to Cyprus, and Paul partners with Silas (Acts 15:39–40). Paul and Silas have already visited the churches in Syria and Cilicia (Acts 15:41)—on the northeast coasts of the Mediterranean—and now travel overland into Galatia in central Asia Minor.Paul and Silas likely would have traveled north from Syrian Antioch to Issus, then west to Tarsus, Paul's hometown. A mountain pass called the Cilician Gates connects Tarsus to Derbe. Lystra is west and a bit north of Derbe. The last time Paul visited, the locals first tried to offer sacrifices to him and Barnabas as Hermes and Zeus, then stoned Paul and left him for dead (Acts 14:8–19). This visit is less eventful.
It's unclear if Paul had met Timothy on his first visit. Timothy's mother, Eunice, and grandmother, Lois, trained him well in Christianity and Judaism before this meeting (2 Timothy 1:5; 3:14–15). Paul will take him on, training him as his "true child in the faith" (1 Timothy 1:2). Despite his youth (1 Timothy 4:12), Timothy will eventually be the pastor of the church in Ephesus (1 Timothy 1:3). First, however, Paul must make sure the older Jews will accept him as their spiritual authority.
Because Timothy's mother is Jewish, he is Jewish. Because his father is Greek, he is not circumcised. Even as a Jew, Timothy does not have to be circumcised to be saved. But Paul knows it will be easier for Timothy to minister to fellow Jews if they don't get hung up on the traditions of his ancestors. So, though the primary purpose of Paul's trip is to assure Gentiles they don't have to be circumcised to worship God and live life with Jews, Paul does circumcise Timothy (Acts 16:3).