On the other hand, parish priests and archdeacons, when they enter religion, resign their cure, in order to enter the state of perfection. This very fact shows the excellence of the religious life. When religious who are not in orders are admitted to the clerical state and to the sacred orders, they are clearly promoted to something better, as stated: this is indicated by the very way in which Jerome expresses himself: "So live in the monastery as to deserve to be a clerk."
Reply to Objection 5: Parish priests and archdeacons are more like bishops than religious are, in a certain respect, namely as regards the cure of souls which they have subordinately; but as regards the obligation in perpetuity, religious are more like a bishop, as appears from what we have said above (AA[5],6).
Reply to Objection 6: The difficulty that arises from the arduousness of the deed adds to the perfection of virtue; but the difficulty that results from outward obstacles sometimes lessens the perfection of virtue---for instance, when a man loves not virtue so much as to wish to avoid the obstacles to virtue, according to the saying of the Apostle ( 1 Cor. 9:25 ), "Everyone that striveth for the mastery refraineth himself from all things": and sometimes it is a sign of perfect virtue---for instance, when a man forsakes not virtue, although he is hindered in the practice of virtue unawares or by some unavoidable cause. In the religious state there is greater difficulty arising from the arduousness of deeds; whereas for those who in any way at all live in the world, there is greater difficulty resulting from obstacles to virtue, which obstacles the religious has had the foresight to avoid.