This book gives us an indication why the best theologians in the Netherlands were ready to swear the Solemn League and Covenant with their brethren in the British Isles (before Cromwell and his forces ruined these plans for a united international Protestant testimony).
It shows us that the best Dutch Synods agreed with the British Covenanters regarding the civil magistrate (establishments), God's law, anti-tolerationism, historical testimony, true unity, false teachers, the Sabbath, "Roman feast days," worship, etc.
For example, in the section "The Organ in the Worship Service and the Singing of Hymns," we read,
"With one word, we judge this and other novelties, in these carefree days, a useless hindrance. This we also say of the introduction of new hymn-books, and present day ditties, which we do not find in God's Word; as also the playing and peeping of organs in the Church. The former are all against the decrees of our Synods. See about singing in the Church, the National Synod of Dordt held in 1578, art. 76; the National Synod held in Middelburg, 1581, art. 51; the National Synod held in the Hague, 1586, art 62; at which gatherings hymns not found in Scripture are expressly forbidden (in a footnote: those who would like to know more about singing of the Psalms, from the Old as well as the New Testament, can read the learned treatise by S. Omius, called 'Dissertation', the first book. Chapter 5, cap. 3).
It is known from Church history, that those who are after novelties, by introducing man-made hymns and errors, have corrupted the Congregation. Although these people have no wrong motives, it is nevertheless not advisable to follow in their steps, since we may receive from them copper instead of gold, as the Pious Peter Martyr witnessed about the time hymns were introduced into the Roman Church. See Peter Martyr on 1 Cor. 14:26.
The words of lord van Aldegonde in this respect are remarkable. In the introduction to his book of Psalms he says, 'The experience of earlier days has taught us that it is often harmful to introduce something which is not based on the Scriptures of the Old and New Testaments.' The Synod of Dordt, 1578, art. 77; of Middleburg, 1581; of Gerderland, 1640, art. 3, have all dealt with terminating, when determining the place of the organ in the Church.
The statement made by the Synod of Dordt, 1574, art. 50, needs our special attention; where we read, 'Concerning the use of Organs in the Congregation, we hold that according to 1 Cor. 14:19, it should not have a place in the Church; and where it is still used when the people leave the church, it is of no use but to forget what was heard before;' they witness that it is nothing but frivolity. It is also remarkable that lord Rivet, contending against the papists, mentions several of their authors, who condemn the novelty of the Organ, and point out that is is without profit. Rivet, Cathol. Orthodox. tom. 1, pag. 561.
To know the reason why Organs should be kept out of the church, read our learned theologians and their polemics about Organs against the Lutherans and Papists, see Faukee, about Psalm 45, pag. 20. Also Lodoc. Larenus, in cap. 12 Esa, pag. 47, where we find the story of the duty of Middleburg's consistory to do away with the Organ; Hoornbeek disput. 2, de Psalmodia. thes 7; Rivet, in Exod. cap. 15 vs. 12. Imprimis Gisb. Voetii. Polit. Eccl. part 1, pag. 548. Hospiniamus de Templis, pag. 309. It would be better if this and other novelties were not mentioned." (pp. 151-152)
Translated here for the first time from Dutch into English, this book may be a shocker to those not familiar with the Dutch Reformation and the faithful pronouncements of her Synods.