A priest acts In Persona Christi.
Priests act in persona Christi capitas, which means “in the person of Christ, head of the Church.” That’s why the priest speaks in the first person at Mass, “This is my body, given up for you.” As Pope John Paul II wrote: “The priest offers his humanity to Christ, so that Christ may use him as an instrument of salvation, making him as it were into another Christ.”
The priesthood is a calling.
Christ asks of some men the sacrifice of their lives in following him as his more intimate companions. From all eternity, certain men are called to the priesthood. It is a call inscribed in their nature and because of this, is a call that will bring them fulfillment.
A priest wields a Sacred Power.
When a priest makes the sacraments present, he wields a sacred power from God, in Latin, sacra potestas.
A priest’s soul changes forever.
At ordination, a man’s soul undergoes an ontological change—a change of being—which indelibly marks his soul forever. Once a priest, always a priest.