Objection 1. It would seem that the active life is more excellent than the contemplative. For "that which belongs to better men would seem to be worthier and better," as the Philosopher says (Top. iii, 1). Now the active life belongs to persons of higher rank, namely prelates, who are placed in a position of honor and power; wherefore Augustine says (De Civ. Dei xix, 19) that "in our actions we must not love honor or power in this life." Therefore it would seem that the active life is more excellent than the contemplative.
Objection 2. Further, in all habits and acts, direction belongs to the more important; thus the military art, being the more important, directs the art of the bridle-maker [Ethic. i, 1. Now it belongs to the active life to direct and command the contemplative, as appears from the words addressed to Moses (Exodus 19:21), "Go down and charge the people, lest they should have a mind to pass the" fixed "limits to see the Lord." Therefore the active life is more excellent than the contemplative.
Objection 3. Further, no man should be taken away from a greater thing in order to be occupied with lesser things: for the Apostle says (1 Corinthians 12:31): "Be zealous for the better gifts." Now some are taken away from the state of the contemplative life to the occupations of the active life, as in the case of those who are transferred to the state of prelacy. Therefore it would seem that the active life is more excellent than the contemplative.
On the contrary, Our Lord said (Luke 10:42): "Mary hath chosen the best part, which shall not be taken away from her." Now Mary figures the contemplative life. Therefore the contemplative life is more excellent than the active.
I answer that, Nothing prevents certain things being more excellent in themselves, whereas they are surpassed by another in some respect. Accordingly we must reply that the contemplative life is simply more excellent than the active: and the Philosopher proves this by eight reasons (Ethic. x, 7,8). The first is, because the contemplative life becomes man according to that which is best in him, namely the intellect, and according to its proper objects, namely things intelligible; whereas the active life is occupied with externals. Hence Rachael, by whom the contemplative life is signified, is interpreted "the vision of the principle," [Or rather, 'One seeing the principle,' if derived from rah and irzn; Cf. Jerome, De Nom. Hebr.] whereas as Gregory says (Moral. vi, 37) the active life is signified by Lia who was blear-eyed. The second reason is because the contemplative life can be more continuous, although not as regards the highest degree of contemplation, as stated above (180, 8, ad 2; 181, 4, ad 3), wherefore Mary, by whom the contemplative life is signified, is described as "sitting" all the time "at the Lord's feet." Thirdly, because the contemplative life is more delightful than the active; wherefore Augustine says (De Verb. Dom. Serm. ciii) that "Martha was troubled, but Mary feasted." Fourthly, because in the contemplative life man is more self-sufficient, since he needs fewer things for that purpose; wherefore it was said (Luke 10:41): "Martha, Martha, thou art careful and art troubled about many things." Fifthly, because the contemplative life is loved more for its own sake, while the active life is directed to something else. Hence it is written (Psalm 36:4): "One thing I have asked of the Lord, this will I seek after, that I may dwell in the house of the Lord all the days of my life, that I may see the delight of the Lord." Sixthly, because the contemplative life consists in leisure and rest, according to Psalm 45:11, "Be still and see that I am God." Seventhly, because the contemplative life is according to Divine things, whereas active life is according to human things; wherefore Augustine says (De Verb. Dom. Serm. civ): "'In the beginning was the Word': to Him was Mary hearkening: 'The Word was made flesh': Him was Martha serving." Eighthly, because the contemplative life is according to that which is most proper to man, namely his intellect; whereas in the works of the active life the lower powers also, which are common to us and brutes, have their part; wherefore (Psalm 35:7) after the words, "Men and beasts Thou wilt preserve, O Lord," that which is special to man is added (Psalm 35:10): "In Thy light we shall see light."
Our Lord adds a ninth reason (Luke 10:42) when He says: "Mary hath chosen the best part, which shall not be taken away from her," which words Augustine (De Verb. Dom. Serm. ciii) expounds thus: "Not--Thou hast chosen badly but--She has chosen better. Why better? Listen--because it shall not be taken away from her. But the burden of necessity shall at length be taken from thee: whereas the sweetness of truth is eternal."
Yet in a restricted sense and in a particular case one should prefer the active life on account of the needs of the present life. Thus too the Philosopher says (Topic. iii, 2): "It is better to be wise than to be rich, yet for one who is in need, it is better to be rich..."
Reply to Objection 1. Not only the active life concerns prelates, they should also excel in the contemplative life; hence Gregory says (Pastor. ii, 1): "A prelate should be foremost in action, more uplifted than others in contemplation."
Reply to Objection 2. The contemplative life consists in a certain liberty of mind. For Gregory says (Hom. iii in Ezech.) that "the contemplative life obtains a certain freedom of mind, for it thinks not of temporal but of eternal things." And Boethius says (De Consol. v, 2): "The soul of man must needs be more free while it continues to gaze on the Divine mind, and less so when it stoops to bodily things." Wherefore it is evident that the active life does not directly command the contemplative life, but prescribes certain works of the active life as dispositions to the contemplative life; which it accordingly serves rather than commands. Gregory refers to this when he says (Hom. iii in Ezech.) that "the active life is bondage, whereas the contemplative life is freedom."
Reply to Objection 3. Sometimes a man is called away from the contemplative life to the works of the active life, on account of some necessity of the present life, yet not so as to be compelled to forsake contemplation altogether. Hence Augustine says (De Civ. Dei xix, 19): "The love of truth seeks a holy leisure, the demands of charity undertake an honest toil," the work namely of the active life. "If no one imposes this burden upon us we must devote ourselves to the research and contemplation of truth, but if it be imposed on us, we must bear it because charity demands it of us. Yet even then we must not altogether forsake the delights of truth, lest we deprive ourselves of its sweetness, and this burden overwhelm us." Hence it is clear that when a person is called from the contemplative life to the active life, this is done by way not of subtraction but of addition.
Source: Summa Theologica (New Advent)