The position of a shepherd is one of God given authority and one of utmost reverence. Shepherds are to watch over the individual souls of the local congregation (1 Peter 5:2). Part of watching out for souls is protecting the congregation from false doctrine as well as providing teaching that is profitable to their spiritual growth.
They lead by servitude in the same way that Christ did, by always having the best interest of the souls of which they sheperd over in mind, and not their own personal desires and wishes. Shepherds are appointed by God through the scripture.