Immediately after Saul’s conversion (Acts 9:1-19), he began his preaching ministry in a missionary setting. He had come from Jerusalem to Damascus, fresh from the scene of Stephen’s murder and bent on bringing believers (“any belonging to the Way”) bound in chains to Jerusalem. Damascus was not his home. So powerful was his encounter with Jesus that he “immediately…proclaimed Jesus in the synagogues, saying, “He is the Son of God” (9:20). There was no requirement or coercion from anyone that forced Saul to go through training before he could preach.
I suggest that where the gospel has been received in the power of the Holy Spirit, there is a God-given ability to tell others what has happened to them and who it is that has made the change in their lives, simple though it be. The proof that his preaching was effective was that “all who heard him were amazed. Saul increase all the more in strength and confounded the Jews who lived in Damascus by proving that Jesus was the Christ” (9:21-22). We find the same powerful work of the Spirit with the Thessalonians (1 Thess. 1:5-8).
Do you trust the work of the Holy Spirit in a new believer and encourage them to share their faith and hope in Christ with others who are still without hope in God? The Spirit’s work in a believer is its own witness to the source and the power.