"But you are a chosen race, a royal priesthood, a holy nation, a people for God’s own possession, that you may proclaim the excellence of him who called you out of darkness into his marvelous light." (1 Pet. 2:9)
I urge you, brothers, by the mercies of God, to present your bodies a
living sacrifice, holy, acceptable to God, which is your spiritual
service. 2 Don’t be
conformed to this world, but be transformed by the renewing of your
mind, so that you may prove what is the good, well-pleasing, and
perfect will of God." (Rom. 12:1-2)
"We are therefore ambassadors on behalf of Christ, as though God were entreating by us: we beg you on behalf of Christ, be reconciled to God." (2 Cor. 5:20)
Every believer is a priest who caries out God's work. God granted us access to Him in prayer. God gives us the fruit of the Spirit, esp love, to make us more Christ-like. God made us all ambassadors who share the Gospel. We can use God's Word combined with good teaching to encourage and exhort others. The Holy Spirit gives each of us at least one, spiritual gift to serve in the Body of Christ. We meet together (corporately) to grow and serve together even more effectively.
"He gave some to be apostles; and some, prophets; and some, evangelists; and some, shepherds and teachers; 12 for the perfecting of the saints, to the work of serving, to the building up of the body of Christ" (Eph. 4:11-12)
"Deacons, too, must be serious, sincere in their talk, not addicted to strong drink or dishonest gain" (1 Tim. 3:8)After the canon closed, the best way to look at Ephesians 4:11-12 is what jobs they represent today: missionaries / church-planters; preaching to exhort congregations; sharing the Gospel more effectively; guiding the congregation; teaching God's Word. God still gives us people to do each. Eph. 4:12 says they're to equip the congregation as a whole to get better at these activities. They'll still typically do more of these things since it's their gift.
In 1 Timothy, today's offices are elder (pastor) and deacon. Elders have authority over the church, guide it, and teach God's Word. They're usually shepherds and teachers. A church's first elders might be missionaries, evangelists, or believers of good character who grew into it. The latter often happens if the group transitions from being an informal meeting to a formal church. The general rule in Scripture is that churches are supposed to plant churches. Deacons are servants, often with the gift of helping, who free up the elders to focus on proclaiming God's Word.
Both elders and deacons have specific requirements. Godly character is the most important. That it's the same character requirements that God has for Christians in general tells aspiring servants to focus on developing consistent, godly character. The church body picks elders and deacons from within their own church. Then, they're appointed by existing elders. Although everyone evangelizes, the churches send out their best members to evangelize.