Why does every believer have to be an ambassador for Christ?

Les explains that God's method has always been to use people. From the beginning of the human race, God ordained that human beings, not angels, would promote His salvation, in both the Old Testament and the New. He points out that it is very rare for someone to find salvation entirely alone, without another human being. Because God has arranged for His Word to be promoted by ordinary people, Paul says in 2 Corinthians 5 that every believer is expected to be a minister of reconciliation and an ambassador for Christ. The practical reason is that people cannot call on Him in whom they have not believed, cannot believe if they have not heard, cannot hear without a preacher or proclaimer, and cannot have someone preach unless that person is sent. So believers must be used of God to share what they know with those who have never heard or understood, and to explain it to those who need understanding.