Sharing the gospel is not simply for professionals—God has called you. You are an agent of God with a particular sphere of influence to leverage for His glory.
If you are a Christian, you are a “living letter” (2 Corinthians 3:1–3). Your life demonstrates the truth of the gospel, demanding a response from all around you. At the end of the day, there can be no neutral response to Christ. We will either walk in the blindness of the world or in the light of the Holy Spirit.
Wherever Paul went on his missionary journeys, God raised up other Christians to assist him. In Acts 18, we see this ecclesiastical synergy at work again.