A priest does not exist merely for his own sanctification but for the Sacrifice of Christ and for the Gospel, for the people, for the world. This implies his own perfection: but the perfection of a priest consists essentially in his offering of Christ’s sacrifice perfectly, for himself and for the church. He no longer belongs to himself, whereas a monk can very well belong to himself in a legitimate way, and be concerned almost exclusively with his own progress, leaving the salvation of the world on a secondary plane.
Thomas Merton, The Sign of Jonas