What does Acts 14:23 mean?

Paul's missionary model is to arrive at a new town and find the local synagogue, first. There he will explain how Jesus fulfills Jewish prophecy, gaining converts from both the Jews and the God-fearing Gentiles. Generally, synagogue leaders will respond by evicting Paul and any new Jesus-followers. Paul will continue to teach and reach more converts until the leaders of the city threaten him, assault him, or otherwise convince him to leave.

Paul doesn't abandon these new churches, however. He and Barnabas revisit these cities to establish church elders: good men, chosen by the Holy Spirit, who can take on a leadership role in their own cities. They know they can't directly pastor every church they plant. They must trust that God will equip local people to take on leadership roles so the church can grow. The qualifications for elders are given in 1 Timothy 3:1–7 and Titus 1:5–9, but other notes can be found in James 5:14, 1 Peter 5:1–4, and Hebrews 13:17.

In the future, Paul will return to these churches on both his second and third missionary journeys (Acts 16:1, 4–5; 18:23). Later, as he does with many of the churches he interacts with, he will write them, helping them with specific struggles and questions. The letter to the churches of this first trip is our book of Galatians.

The issue of fasting in the Bible is a complicated one. In the Mosaic law, God told the Israelites to "afflict" themselves on the Day of Atonement (Leviticus 16:29). No one now is sure what it means to "afflict yourself." By the latter part of the Old Testament, Jews thought it meant fasting, but some scholars think it means to refrain from normal grooming or having sex, while others say it means to sacrifice for the sake of social justice or even to sing.