Celsus also urges us to “take office in the government of the country, if that is required for the maintenance of the laws and the support of religion.” But we recognise in each state the existence of another national organization, founded by the Word of God, and we exhort those who are mighty in word and of blameless life to rule over Churches. Those who are ambitious of ruling we reject; but we constrain those who, through excess of modesty, are not easily induced to take a public charge in the Church of God.
And those who rule over us well are under the constraining influence of the great King, whom we believe to be the Son of God, God the Word. And if those who govern in the Church, and are called rulers of the divine nation— that is, the Church— rule well, they rule in accordance with the divine commands, and never suffer themselves to be led astray by worldly policy. And it is not for the purpose of escaping public duties that Christians decline public offices, but that they may reserve themselves for a diviner and more necessary service in the Church of God— for the salvation of men.
And this service is at once necessary and right. They take charge of all— of those that are within, that they may day by day lead better lives, and of those that are without, that they may come to abound in holy words and in deeds of piety; and that, while thus worshipping God truly, and training up as many as they can in the same way, they may be filled with the word of God and the law of God, and thus be united with the Supreme God through His Son the Word, Wisdom, Truth, and Righteousness, who unites to God all who are resolved to conform their lives in all things to the law of God.
Source: Against Celsus (New Advent)