"Then he came to Derbe and Lystra. And behold, a certain disciple was there, named Timothy, the son of a certain Jewish woman who believed, but his father was Greek. He was well spoken of by the brethren who were at Lystra and Iconium. Paul wanted to have him go on with him. And he took him and circumcised him because of the Jews who were in that region, for they all knew that his father was Greek. And as they went through the cities, they delivered to them the decrees to keep, which were determined by the apostles and elders at Jerusalem. So the churches were strengthened in the faith, and increased in number daily" (Acts 16:1-5).
After Paul and Silas left Antioch, they headed north and then west to Derbe and Lystra. Although it is not mentioned, it seems reasonable that they may have stopped at Tarsus, Paul's hometown, (or at least traveled through it) since it was on their way. At Lystra, Paul met or, more likely, was reacquainted with Timothy. There is strong evidence that Paul converted Timothy to Christ, likely on the visit he and Barnabas made there (cf. Acts 14:20; I Cor. 4:17; I Tim. 1:2). If Paul did not have an active role in converting Timothy, at the very least he views him fondly as a genuine Christian. Paul mentors Timothy and treats him like a son in the faith.
This young man was a well respected disciple by those in the region. Paul evidently perceived Timothy's value to their evangelistic efforts and invited Timothy to join Silas and himself on their mission. Timothy's dedication is clearly seen in this context. Not only did he want to go and help preach the gospel and strengthen other Christians, but he was willing to endure a great deal of pain to do so before even leaving home! Timothy was willing to be circumcised to maximize his potential as an evangelist. Let us elaborate on this matter:
"For though I am free from all men, I have made myself a servant to all, that I might win the more; and to the Jews I became as a Jew, that I might win Jews; to those who are under the law, as under the law, that I might win those who are under the law; to those who are without law, as without law (not being without law toward God, but under law toward Christ), that I might win those who are without law; to the weak I became as weak, that I might win the weak. I have become all things to all men, that I might by all means save some. Now this I do for the gospel's sake, that I may be partaker of it with you."
After Timothy had healed and was able to travel, the group left Lystra and preached the gospel though other cities in the region. As they went, they also delivered the decrees which had been determined by the apostles and elders at Jerusalem via the Holy Spirit (cf. Acts 15:28). Their efforts resulted in more Christians being added to the church and each one growing in their knowledge of the faith (i.e., New Testament Christianity).