The priesthood is the supreme gift, a particular calling to share in the mystery of Christ, a calling which confers on us the sublime possibility of speaking and acting in his name. Every time we offer the Eucharist, this possibility becomes a reality. We act in 'persona Christi ' when, at the moment of the consecration, we say the words: "This is my body which will be given up for you.... This is the cup of my blood, the blood of the new and everlasting covenant. It will be shed for you and for all so that sins may be forgiven. Do this in memory of me." We do precisely this: with deep humility and profound thanks. This exalted yet simple action of our daily mission as priests opens up our humanity, so to speak, to its furthermost limits....."
Pope John Paul II, March 13, 1994