An ambassador is someone authorized to act on behalf of a higher authority; they serve as a representative. The common usage today is a person who represents their country to a foreign government.
Some translations of the Bible use the word ambassador in this sense, as someone who acts on God‘s behalf as his representative to others.
For example:
Jesus sent out his twelve disciples as his ambassadors (Mark 6:7, Amplified version).
Paul said he was Jesus’ ambassador (Ephesians 6:20 and Philemon 1:9, Amplified version).
Followers of Jesus serve as his ambassadors (2 Corinthians 5:20), with the responsibility to act rightly and represent him properly.
Key verse about Ambassador: We are therefore Christ’s ambassadors, as though God were making his appeal through us. We implore you on Christ’s behalf: Be reconciled to God (2 Corinthians 5:20, NIV).
A lifelong student of the Bible, Peter DeHaan, PhD, wrote the 1,000-page website ABibleADay.com to encourage people to explore the Bible. His main blog and many books urge Christians to push past the status quo and reconsider how they practice their faith in every area of their lives.