The “John” here (v.13) is John Mark, who wrote the gospel of Mark. He went with Paul to minister to his physical needs (v.5), but probably thought Paul would go around healing blindness, not inflicting it (v.11), so he went home here.
The phrase “Paul and his company” is the first time Paul’s mentioned first (cf.13:2,7). This reminds us that Acts is all about the transition from God’s program for Israel in the 4 gospels to His program for us in Paul’s epistles. That’s why Acts comes between the gospels and Paul’s epistles, and it’s why, from this point forward in Acts, Paul is given top billing, and is the focus of everything that God is doing.
Luke tells us Paul went to Antioch “in Pisidia” (Acts 13:14) because it was a different Antioch than the one in Syria where he and Barnabas were ordained (Acts 13:1-3). The Lord sent Paul to the Gentiles, but he went to a synagogue here because, even though the nation rejected Christ, there were still individual Jews who God knew would believe if given a chance, so He gave them that chance through Paul.
The Jews in that synagogue must have heard Paul was in town, for they “sent” to him to preach after the Scripture Reading (v.15). That means it was a large synagogue. Their reading always included a little of the law (cf.Acts15: 1) and the prophets (13:27). They had “rulers” in their synagogues, but one “chief” ruler (18:8,17), just as we have a plurality of teaching elders in our churches, but one pastor.
Paul addressed the Jews in the synagogue (13:16), and any Gentiles who feared God. That’s different than what Peter did at Pentecost. He ignored Gentiles (Acts 2:14,22,36).
But we know Paul was mainly speaking to Jews, because he reminds them that God chose their fathers (13:16) i.e., Abraham, Isaac and Jacob (cf.Acts 3:13), and sent them a savior named Moses. God “exalted” them (13:17) by multiplying them (cf.Ex.1:7), and brought them out of Egypt with a “high arm” (Acts 13:17) of power (Ex.14:8,28; 33:3,4).
But the people of Israel paid God back by rebelling against Him in the wilderness (Acts 13:18). So God sent them another savior, Joshua, who helped them evict the Canaanites from the land God promised them (v.19). Then He sent them a bunch of saviors called judges (v.20). Then they fell into a pattern: they’d rebel against God, He’d judge them, they’d cry to Him, and He’d send them another savior judge (Judges 2:16-20). Paul is reminding them of this to point out they recently rebelled against the last Savior God sent them!
God sent them thirteen judges: 12 He approved of, one He didn’t. That’s a type of how the Lord had 12 apostles: 12 He approved of, and one He had to replace. God set things up in Israel the way He’s going to set things up in the kingdom (Isa.1:26), when He’ll restore their judges (cf.Mt.19:28).
But the Jews didn’t like being ruled God’s way and asked for a king (v.21). God agreed (ISam.8:4-7), but gave them a king who was a type of the antichrist. Saul reigned before David, a type of Christ, just as Antichrist will reign in the Tribulation before Christ reigns in the kingdom. He hated David the way the beast will hate Christ. He died by the sword the way Antichrist will. God set David on Israel’s throne the way He’ll set Christ on it (Acts 13:22cf.Jer.23:5).
Paul knew that those Jews knew that Christ would be of David’s seed, so he reminded them Jesus was (Acts 13:23). He also knew they knew that God said He’d send Elijah back before He sent Messiah (Mal.4:5,6), so Paul reminds them that God sent John the Baptist first, in the spirit of Elijah (Lu.1:16,17). If Israel would have received the kingdom, John would have been Elijah (Mt.11:11-14). As it is, God will send Elijah himself back before the Lord’s second coming to Israel (Rev.11:3,6 cf. James 5:17).