17 (Relationship to the world and temporal goods, and voluntary poverty.) In their friendly and brotherly dealings with one another and with other men, priests are able to learn and appreciate human values and esteem created goods as gifts of God. By living in the world, let priests know how not to be of the world, according to the word of our Lord and Master. By using the world as those who do not use it, let them achieve that freedom whereby they are free from every inordinate concern and become docile to the voice of God in their daily life. From this freedom and docility grows spiritual discretion in which is found the right relationship to the world and earthly goods. Such a right relationship is of great importance to priests, because the mission of the Church is fulfilled in the midst of the world and because created goods are altogether necessary for the personal development of man. Let them be grateful, therefore, for all that the heavenly Father has given them to lead a full life rightly, but let them see all that comes to them in the light of faith, so that they might correctly use goods in response to the will of God and reject those which are harmful to their mission. For priests who have the Lord as their "portion and heritage," (Num 18:20) temporal goods should be used only toward ends which are licit according to the doctrine of Christ and the direction of the Church. Ecclesiastical goods, properly so called, according to their nature and ecclesiastical law, should be administered by priests with the help of capable laymen as far as possible and should always be employed for those purposes in the pursuit of which it is licit for the Church to possess temporal goods-namely, for the carrying out of divine worship, for the procuring of honest sustenance for the clergy, and for the exercise of the works of the holy apostolate or works of charity, especially in behalf of the needy. Those goods which priests and bishops receive for the exercise of their ecclesiastical office should be used for adequate support and the fulfillment of their office and status, excepting those governed by particular laws. That which is in excess they should be willing to set aside for the good of the Church or for works of charity. Thus they are not to seek ecclesiastical office or the benefits of it for the increase of their own family wealth. Therefore, in no way placing their heart in treasures, they should avoid all greediness and carefully abstain from every appearance of business. Priests, moreover, are invited to embrace voluntary poverty by which they are more manifestly conformed to Christ and become eager in the sacred ministry. For Christ, though he was rich, became poor on account of us, that by his need we might become rich. And by their example the apostles witnessed that a free gift of God is to be freely given, with the knowledge of how to sustain both abundance and need. A certain common use of goods, similar to the common possession of goods in the history of the primitive Church, furnishes an excellent means of pastoral charity. By living this form of life, priests can laudably reduce to practice that spirit of poverty commended by Christ. Led by the Spirit of the Lord, who anointed the Savior and sent him to evangelize the poor, priests, therefore, and also bishops, should avoid everything which in any way could turn the poor away. Before the other followers of Christ, let priests set aside every appearance of vanity in their possessions. Let them arrange their homes so that they might not appear unapproachable to anyone, lest anyone, even the most humble, fear to visit them. SECTION THREEAids to the Life of Priests
Source: Presbyterorum Ordinis (Vatican.va)