Christ has appointed the office of (ruling) elder in his church and gifted men to be called by the church to serve as under-shepherds. Ruling elders are to help in the government of the church and the ministry of prayer and the Word. They are to have a particular concern for the doctrine and conduct of the minister.
In addition to elders, Christ has gifted men to be called by the church to serve as deacons. The office of deacon is one of service, ministering mercy to those in need and to help provide for the elders that they might labor in prayer and the Word.