From The Book of Church Order of the Presbyterian Church in America
8-1. This office is one of dignity and usefulness. The man who fills it has in Scripture different titles expressive of his various duties. As he has the oversight of the flock of Christ, he is termed bishop or pastor. As it is his duty to be grave and prudent, an example to the flock, and to govern well in the house and Kingdom of Christ, he is termed presbyter or elder. As he expounds the Word, and by sound doctrine both exhorts and convinces the gainsayer, he is termed teacher. These titles do not indicate different grades of office, but all describe one and the same office.
8-2. He that fills this office should possess a competency of human learning and be blameless in life, sound in the faith and apt to teach. He should exhibit a sobriety and holiness of life becoming the Gospel. He should rule his own house well and should have a good report of them that are outside the Church.