Acts 14:21-22
21 And when they had preached the gospel to that city, and had taught many, they returned again to Lystra, and to Iconium, and Antioch,
22 Confirming the souls of the disciples, and exhorting them to continue in the faith, and that we must through much tribulation enter into the kingdom of God.
The Grace New Testament Commentary - Acts 14:22
14:22 Paul and Barnabas had experienced these troubles as seasoned believers. On the other hand, the new believers witnessed much turmoil soon after their conversion. Aware of this, Paul and Barnabas returned to these places (despite their own negative experiences there as well as the possibility of more opposition), strengthening the souls of the disciples, exhorting them to continue in the faith.
Their compassionate strategy shows that believers need encouragement as an aid to their perseverance. They can never lose the gift of eternal life. They can, however, veer off the path of discipleship especially in the context of its hardships. Paul and Barnabas assured them that "We must through many tribulations enter the kingdom of God." Persevering through hardships constitutes a normal experience for all disciples as they await the establishment of, and their entrance into, the future messianic kingdom.