"And when they had preached the gospel to that city and made many disciples, they returned to Lystra, Iconium, and Antioch, strengthening the souls of the disciples, exhorting them to continue in the faith, and saying, 'We must through many tribulations enter the kingdom of God.' So when they had appointed elders in every church, and prayed with fasting, they commended them to the Lord in whom they had believed. And after they had passed through Pisidia, they came to Pamphylia. Now when they had preached the word in Perga, they went down to Attalia. From there they sailed to Antioch, where they had been commended to the grace of God for the work which they had completed. Now when they had come and gathered the church together, they reported all that God had done with them, and that He had opened the door of faith to the Gentiles. So they stayed there a long time with the disciples" (Acts 14:21-28).
After being stoned and left for dead at Lystra, Paul continues on, with Barnabas, to Derbe. Luke does not provide much information in regards to their work there, other than the fact that they "made many disciples." Then, they turned around and retraced their steps, more or less, by going back through most of the same cities they had visited earlier in their evangelistic journey. Specifically, they revisited Lystra, Iconium, Antioch in Pisidia, and Perga. They sailed from Attalia back "home," to Antioch in Syria. Their route back to their starting point did have them bypass Cyprus. It is fascinating that Paul and Barnabas turn back to the same cities they had suffered so much abuse in when they could have easily traveled on to Tarsus (Paul's hometown) and then down to Antioch in Syria. Obviously, these are men of courage and purpose!
What was their purpose in revisiting these cities? Originally, they had gone to evangelize and convert as many souls as possible to Christ. That was still part of their purpose, of course. However, these cities where they are returning to now have a Christian population; there is a congregation of believers in each city. Paul and Barnabas (the great encourager) go back to each of these congregations to strengthen the brethren in the faith! That is their primary purpose now. Those who are converted to Christ must be conserved! The welfare of the infant congregations is deemed more important than the personal safety of Paul and Barnabas. They exhorted these followers of Jesus Christ not to grow weary but to remain strong and loyal to the Lord, no matter what the cost! These new converts were surrounded by unbelieving Jews and idolatrous Gentiles. They lived in the midst of many dangers and temptations. Many family and social ties had been severed. They needed encouragement! They were being persecuted and would faithfully suffer much ("many tribulations") for the cause of Christ if they were to eventually enter heaven (cf. II Tim. 3:12). It is worth observing here that it must be possible for a child of God to fall away from the Lord and be lost. If not, why would Paul and Barnabas exhort disciples to "continue in the faith"? Why even bother with this if they could never be lost? Their exhortation here implies that doctrine is important for all Christians.
Having good leadership in each congregation (particularly when Paul and Barnabas weren't around) would be very important to its overall stability and ability to remain steadfast. As go the leaders, so goes the congregation. Such is still true today. It was God's will that each congregation have qualified men serve as elders (cf. I Tim. 3 & Titus 1), and Luke records that Paul and Barnabas appointed elders in each congregation. Some have wondered how this would be possible in such a short span of time. How could men be ready to become elders who were just converted to Jesus Christ no more than a year or two ago (perhaps even sooner in some cases)? Although such would not be possible today, it would not have been as problematic then because of one primary difference. The early church had the benefit of the miraculous gifts of the Spirit, and certain gifts (e.g., the gift of wisdom, cf. I Cor. 12:8) would have been able to equip men to be shepherds much more quickly than strictly through the natural process of maturity via experience.
After returning to Antioch in Syria, Paul and Barnabas made a thorough report of their activities (which would have included both their successes and challenges) to the brethren there. They had done what the Holy Spirit had intended for them to do on their journey (cf. Acts 13:2). They give God the glory, knowing that He used them to reach out to the Gentiles with the saving gospel of Christ. They were opening "the door of faith" and it was up to the Gentiles to walk through by believing and obeying the gospel! Although some Jews were still inclined to be exclusive in their thinking, the evidence was becoming clearer and clearer--the church of Christ was not just for Jews but for all peoples! Paul and Barnabas then remained in Antioch for a long time.