Objection 1. It would seem that the religious state is more perfect than that of prelates. For our Lord said (Matthew 19:21): "If thou wilt be perfect, go" and "sell" all [Vulgate: 'what'] "thou hast, and give to the poor"; and religious do this. But bishops are not bound to do so; for it is said (XII, qu. i, can. Episcopi de rebus): "Bishops, if they wish, may bequeath to their heirs their personal or acquired property, and whatever belongs to them personally." Therefore religious are in a more perfect state than bishops.
Objection 2. Further, perfection consists more especially in the love of God than in the love of our neighbor. Now the religious state is directly ordered to the love of God, wherefore it takes its name from "service and homage to God," as Dionysius says (Eccl. Hier. vi); [Quoted above 5 whereas the bishop's state would seem to be ordered to the love of our neighbor, of whose cure he is the "warden," and from this he takes his name, as Augustine observes (De Civ. Dei. xix, 19). Therefore it would seem that the religious state is more perfect than that of bishops.
Objection 3. Further, the religious state is directed to the contemplative life, which is more excellent than the active life to which the episcopal state is directed. For Gregory says (Pastor. i, 7) that "Isaias wishing to be of profit to his neighbor by means of the active life desired the office of preaching, whereas Jeremias, who was fain to hold fast to the love of his Creator, exclaimed against being sent to preach." Therefore it would seem that the religious state is more perfect than the episcopal state.
On the contrary, It is not lawful for anyone to pass from a more excellent to a less excellent state; for this would be to look back [Cf. (Luke 9:62). Yet a man may pass from the religious to the episcopal state, for it is said (XVIII, qu. i, can. Statutum) that "the holy ordination makes a monk to be a bishop." Therefore the episcopal state is more perfect than the religious.
I answer that, As Augustine says (Gen. ad lit. xii, 16), "the agent is ever more excellent than the patient." Now in the genus of perfection according to Dionysius (Eccl. Hier. v, vi), bishops are in the position of "perfecters," whereas religious are in the position of being "perfected"; the former of which pertains to action, and the latter to passion. Whence it is evident that the state of perfection is more excellent in bishops than in religious.
Reply to Objection 1. Renunciation of one's possessions may be considered in two ways. First, as being actual: and thus it is not essential, but a means, to perfection, as stated above (Article 3). Hence nothing hinders the state of perfection from being without renunciation of one's possessions, and the same applies to other outward practices. Secondly, it may be considered in relation to one's preparedness, in the sense of being prepared to renounce or give away all: and this belongs directly to perfection. Hence Augustine says (De QQ. Evang. ii, qu. 11): "Our Lord shows that the children of wisdom understand righteousness to consist neither in eating nor in abstaining, but in bearing want patiently." Wherefore the Apostle says (Philippians 4:12): "I know... both to abound and to suffer need." Now bishops especially are bound to despise all things for the honor of God and the spiritual welfare of their flock, when it is necessary for them to do so, either by giving to the poor of their flock, or by suffering "with joy the being stripped of" their "own goods" [Hebrews 10:34].
Reply to Objection 2. That bishops are busy about things pertaining to the love of their neighbor, arises out of the abundance of their love of God. Hence our Lord asked Peter first of all whether he loved Him, and afterwards committed the care of His flock to him. And Gregory says (Pastor. i, 5): "If the pastoral care is a proof of love, he who refuses to feed God's flock, though having the means to do so, is convicted of not loving the supreme Pastor." And it is a sign of greater love if a man devotes himself to others for his friend's sake, than if he be willing only to serve his friend.
Reply to Objection 3. As Gregory says (Pastor. ii, 1), "a prelate should be foremost in action, and more uplifted than others in contemplation," because it is incumbent on him to contemplate, not only for his own sake, but also for the purpose of instructing others. Hence Gregory applies (Hom. v in Ezech.) the words of Psalm 144:7, "They shall publish the memory... of Thy sweetness," to perfect men returning after their contemplation.
Source: Summa Theologica (New Advent)