2 Corinthians 5:20 - 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. 

https://www.biblegateway.com/passage/?search=2+Corinthians+5%3A20&version=NIV

You are Christ's ambassador wherever you go.

Acts 1:8 - “You will receive power when the Holy Spirit comes on you; and you will be my witnesses in Jerusalem, and in all Judea and Samaria, and to the ends of the earth.” 

https://www.biblegateway.com/passage/?search=Acts+1%3A8&version=NIV

Matthew 28:18-20 - Then Jesus came to them and said, “All authority in heaven and on earth has been given to me. Therefore go and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, and teaching them to obey everything I have commanded you. And surely I am with you always, to the very end of the age.”

https://www.biblegateway.com/passage/?search=Matthew+28%3A18-20&version=NIV

You are Christ's ambassador wherever you give financial support.

2 Corinthians 9:11 - You will be enriched in every way so that you can be generous on every occasion, and through us your generosity will result in thanksgiving to God. 

https://www.biblegateway.com/passage/?search=2+Corinthians+9%3A11&version=NIV

Philippians 1:3-6 - I thank my God every time I remember you. In all my prayers for all of you, I always pray with joy because of your partnership in the gospel from the first day until now, being confident of this, that he who began a good work in you will carry it on to completion until the day of Christ Jesus. 

https://www.biblegateway.com/passage/?search=Philippians+1%3A3-6&version=NIV

You are Christ's ambassador wherever you support through prayer.

Ephesians 6:18-20 - And pray in the Spirit on all occasions with all kinds of prayers and requests.  With this in mind, be alert and always keep on praying for all the Lord’s people. Pray also for me, that whenever I speak, words may be given me so that I will fearlessly make known the mystery of the gospel, for which I am an ambassador in chains.  Pray that I may declare it fearlessly, as I should. 

https://www.biblegateway.com/passage/?search=Ephesians+6%3A18-20&version=NIV