Objection 1. It would seem that men renounce temporal goods by receiving the tonsure, for when they are tonsured they say: "The Lord is the portion of my inheritance." But as Jerome says (Ep. ad Nepot.), "the Lord disdains to be made a portion together with these temporal things." Therefore he renounces temporalities.
Objection 2. Further, the justice of the ministers of the New Testament ought to abound more than that of the ministers of the Old Testament (Matthew 5:20). But the ministers of the Old Testament, namely the Levites, did not receive a portion of inheritance with their brethren (Deuteronomy 10; Deuteronomy 18). Therefore neither should the ministers of the New Testament.
Objection 3. Further, Hugh says (De Sacram. ii) that "after a man is made a cleric, he must from thenceforward live on the pay of the Church." But this would not be so were he to retain his patrimony. Therefore he would seem to renounce it by becoming a cleric.
On the contrary, Jeremias was of the priestly order (Jeremiah 1:1). Yet he retained possession of his inheritance (Jeremiah 32:8). Therefore clerics can retain their patrimony.
Further, if this were not so there would seem to be no difference between religious and the secular clergy.
I answer that, Clerics by receiving the tonsure, do not renounce their patrimony or other temporalities; since the possession of earthly things is not contrary to the Divine worship to which clerics are appointed, although excessive care for such things is; for as Gregory says (Moral. x, 30), "it is not wealth but the love of wealth that is sinful."
Reply to Objection 11. The Lord disdains to be a portion as being loved equally with other things, so that a man place his end in God and the things of the world. He does not, however, disdain to be the portion of those who so possess the things of the world as not to be withdrawn thereby from the Divine worship.
Reply to Objection 2. In the Old Testament the Levites had a right to their paternal inheritance; and the reason why they did not receive a portion with the other tribes was because they were scattered throughout all the tribes, which would have been impossible if, like the other tribes, they had received one fixed portion of the soil.
Reply to Objection 3. Clerics promoted to holy orders, if they be poor, must be provided for by the bishop who ordained them; otherwise he is not so bound. And they are bound to minister to the Church in the Order they have received. The words of Hugh refer to those who have no means of livelihood.
Source: Summa Theologica (New Advent)