IX. Although the care of religion belongs to the magistrate, political and ecclesiastical power are not on this account confounded. They are concerned with it in a different way; some are the duties of that, others of this. The former is concerned only about extrinsic things, as to their external disposition and order (which belong to the worship of God); the latter, however, about internal things (to wit, the administration of those things which pertain to the worship of God). He does not exercise the ministry of the word who admonishes and corrects a minister erring in doctrine or delinquent in life and removes an obstinate or scandalous one. He does not baptize who prohibits the profanation of baptism, who takes care that holy things should be done in a holy manner.
X. As it is not lawful for bishops to draw the sword, so neither is it lawful for princes and civilians to handle the thurible [sic]; as to the preaching of the word, the administration of the sacraments and other things which formally belong to pastors and are of the essential reason of their office. But it does not thence follow that the other functions concerning the government of the church do not belong to the believing magistrate. Although it is not lawful for bishops to engage in politics or to plead in court, still it is lawful and incumbent upon them to admonish and to exhort magistrates to do their duty. And if they at any time fall in it, they are to rebuke and to denounce the judgment of God against them. So, in turn, although the preaching of the word does not pertain to magistrates, still it is lawful for them to admonish and rebuke bishops and pastors neglecting or wandering from their office; nay, also to bring to order transgressors and to take care that the ministry be not corrupted and religion to suffer no harm.
Francis Turretin, Institutes of elenctic theology, trans. G. M. Giger, ed. J. T. Dennison (1679; 3 vols, Philipsburgh, 1992), iii, 318-19.