Having the command to proclaim the gospel and administer the sacraments, believers may appoint some from their midst to proclaim the gospel in specific ways, which may or may not include administration of the sacraments. Such proclamation as Christ’s ambassadors is public in the sense that those appointed, like the apostles, represent other believers.
Those appointed to proclaim the gospel as representatives of the church are to do so according to their gifts from the Spirit (1 Peter 4:1; Romans 12:6-8; 1 Cor. 12:4-6, 27-30). As manifestations of the coming kingdom of God, such gifts transcend the callings all have to their vocations.
Thus, all of those called to proclaim the gospel as representatives of the church are gifts of the ascended Christ to his church (see Ephesians 4:11). Just as the Good Shepherd represents the church as the head of the body, apostles and other public ministers of the word represent the church as its tongue. All public ministers are servants of the church (1 Corinthians 3:21) following the Servant of all (Mark 10:45; cf. Mark 9:35).