“In these words most evidently is expressed unto us, why God wills that we avoid all fellowship with idolatry, and with the maintainers of the same; in which are three things appertaining to our purpose chiefly to be noted. First, that the Holy Ghost pronounces and gives warning unto us, that maintainers of idolatry, and provokers to the same, intend to draw us from God; and therefore he wills that we neither obey them (be they kings or be they queens), neither yet that we conceal their impiety (were they son, daughter, or wife), if we will have the league to stand betwixt God and us [Deut. 13:6-18]. And here is the confirming of my first cause, why it is necessary that we avoid idolatry, because that otherwise we declare ourselves little to regard the league and covenant of God; for that league requires that we declare ourselves enemies to all sorts of idolatry. Secondly, it is to be noted, that idolatry so incenses and kindles the wrath of God, that it is never quenched till the offenders, and all that they possess, are destroyed from the earth; for he commanded them to be stoned to death, and their substance to be burnt; and if a city offended, that it shall be altogether destroyed without mercy. This may appear a severe and rigorous judgment. But if you shall consider the cause, God’s great mercy towards us shall be espied; for thereunto he declares himself [an] enemy unto our enemies. For all those that would draw us from God ( be they kings or queens), being of the devil’s nature, are enemies unto God, and therefore God wills that in such cases we declare ourselves enemies unto them; because he would that we should understand how odious is idolatry in his presence, and how that we cannot keep the league betwixt him and us inviolate if we favour, follow, or spare idolaters. ‘Lord, open our eyes that we may understand the great necessity of this thy precept. Amen.'”
Selected Writings, 1:172
Exclusive Psalmody 