Priests and deacons are the Ordinary Ministers of Holy Communion (EMoHC). When there are too many people at Mass for them to distribute the Blessed Sacrament to everyone, Extra-Ordinary Ministers of Holy Communion are called upon to help. EMoHC's must, with their whole being, believe in the True Presence. They distribute the Body, Blood, Soul, and Divinity of our Lord Jesus Christ to their fellow parishioners. It is a humbling ministry.
The Qualities of EMoHC
From the book Eucharist by Bishop Robert Barron:
“This is why I tell people to be very careful when they approach the Eucharist. Were the elements simply symbols - inventions of our own spiritual creativity and desire - they would pose no particular threat, but since they are the power and presence of God, they will change the one who consumes them. When the communicant says “Amen” and receives the proffered host and chalice, he’d better be prepared to live an eternal life.”