27 Bishops, as vicars and ambassadors of Christ, govern the particular churches entrusted to them by their counsel, exhortations, example, and even by their authority and sacred power, which indeed they use only for the edification of their flock in truth and holiness, remembering that he who is greater should become as the lesser and he who is the chief become as the servant. This power, which they personally exercise in Christ's name, is proper, ordinary and immediate, although its exercise is ultimately regulated by the supreme authority of the Church, and can be circumscribed by certain limits, for the advantage of the Church or of the faithful. In virtue of this power, bishops have the sacred right and the duty before the Lord to make laws for their subjects, to pass judgment on them and to moderate everything pertaining to the ordering of worship and the apostolate. The pastoral office or the habitual and daily care of their sheep is entrusted to them completely; nor are they to be regarded as vicars of the Roman Pontiffs, for they exercise an authority that is proper to them, and are quite correctly called "prelates," heads of the people whom they govern. Their power, therefore, is not destroyed by the supreme and universal power, but on the contrary it is affirmed, strengthened and vindicated by it, since the Holy Spirit unfailingly preserves the form of government established by Christ the Lord in His Church. A bishop, since he is sent by the Father to govern his family, must keep before his eyes the example of the Good Shepherd, who came not to be ministered unto but to minister, and to lay down his life for his sheep. Being taken from among men, and himself beset with weakness, he is able to have compassion on the ignorant and erring. Let him not refuse to listen to his subjects, whom he cherishes as his true sons and exhorts to cooperate readily with him. As having one day to render an account for their souls, he takes care of them by his prayer, preaching, and all the works of charity, and not only of them but also of those who are not yet of the one flock, who also are commended to him in the Lord. Since, like Paul the Apostle, he is debtor to all men, let him be ready to preach the Gospel to all, and to urge his faithful to apostolic and missionary activity. But the faithful must cling to their bishop, as the Church does to Christ, and Jesus Christ to the Father, so that all may be of one mind through unity, and abound to the glory of God.
Source: Lumen Gentium (Vatican.va)