We believe that those Holy Scriptures fully contain the will of God, and whatsoever man ought to believe unto salvation is sufficiently taught therein. For since the whole manner of worship which God requires of us is written in them at large, it is unlawful for any one, though an apostle, to teach otherwise than we are now taught in the Holy Scriptures: nay, though it were an angel from heaven, as the apostle Paul says. For since it is forbidden to add unto or take away anything from the Word of God, it does thereby evidently appear that the doctrine thereof is most perfect and complete in all respects. Neither may we consider any writings of men, however holy these men may have been, of equal value with those divine Scriptures, nor ought we to consider custom, or the great multitude, or antiquity, or succession of times and persons, or councils or decrees or statutes, as of equal value with the truth of God, since the truth is above all; for all men or of themselves liars, and more van than vanity itself. Therefore we reject with all our hearts whatever does not agree with this infallible rule, as the apostles have taught us saying, Test the spirits, whether they are of God. Likewise: any one comes to you and brings not this teaching, receive him not into your house (Art. 7)
We also believe that although it is useful and good for those who govern the churches to establish and set up a certain order among themselves for maintaining the body of the church, they ought always to guard against deviating from what Christ, our only Master, has ordained for us. Therefore we reject all human innovations and all laws imposed on us, in our worship of God, which bind and force our consciences in any way (Art. 32).
Belgic Confession (1561; emphasis added)