What does Acts 18:22 mean?

Having completed his second missionary voyage, Paul is home. He set sail from Ephesus, on the western coast of modern-day Turkey, and lands in Caesarea Maritima, the major port of the eastern coast of the Mediterranean where the Romans rule over Samaria and Judea.

The text says he goes "up" to greet the church. This doesn't refer to the church in Caesarea but in Jerusalem; Jerusalem is about 2,600 feet in elevation and Caesarea is at sea level. The "church" is the original church, started by the disciples on the Day of Pentecost when the Holy Spirit fell on 3,000 people (Acts 2), and pastored by James, the half-brother of Jesus (Galatians 2:9).

The text doesn't say why Paul goes to Jerusalem. He may need to complete the requirements for a Nazirite vow (Acts 18:18) which includes sacrificing at the temple (Numbers 6:13–20). Although Paul relies on Jesus for salvation, he has no problem participating in Jewish rituals (Acts 21:23–26). Another possibility is that he wants to be there for the Passover. Or, he could be reporting how he planted churches in Macedonia and Greece and getting any new instruction the apostles may have for him (Acts 15:2; Galatians 2:1–2).

When Paul leaves Jerusalem, he will return to Syrian Antioch in the far northeast corner of the Mediterranean Sea. After an extended visit, he will set out for his third missionary journey, visiting the same places as the second. This time, however, when he returns to Jerusalem, he will be arrested and imprisoned (Acts 19—28)—but he will finally reach Rome where he has been longing to go for years (Romans 1:11–15).