What qualifications does Jesus require for those who would administer sacraments like baptism and communion?

As a laymen without ordination of any kind, I know it would be sacrilegious for me to conduct a baptism or preside at holy communion. But I'm wondering how a Christian leader would receive such incredible authority, either to wash away original sin and help a new believer become a child of God, or to confidently ask the Holy Spirit to change bread and wine into the body and blood of Christ. Evidence either from scripture or from Christian tradition would be welcome.