All Christians are to be witnesses for the Lord, but some are called by God and sent out by the church for specific assignments, i.e., Paul in Acts 13. When they cross cultures we call them missionaries, a specific set of witnesses. “Therefore, if anyone is in Christ, he is a new creature; the old has gone, the new has come! All of this is from God, who reconciled us to Himself through Christ and gave us the ministry of reconciliation… And he has committed to us the message of reconciliation.”2 Corinthians 5:17-19