"The Early church did not use instrumental music in its worship.... They considered the practice as pagan or Jewish rather than Christian.

Dr. Hughes Oliphant Old, in his work The Patristic Roots of Reformed Worship says: "As is well known, the ancient church did not admit the use of instrumental music in worship. It was looked upon as a form of worship which like the sacrifices of the Jerusalem temple prefigured the worship in spirit and truth....'" (Needham, The Presbyterian, #32, p. 35). Heart and Voice: Instruments in Christian Worship Not Authorized (1873), by James Glasgow, contains advanced exegetical study of the second commandment (from the Hebrew) and upholds the regulative principle of worship.

It's a vindication of the Westminster Confession against all ritualistic practices that give the Church the power to decree rites and ceremonies -- a power that denies the sovereignty of God. Glasgow proclaims that he has "sought to vindicate the words of the Westminster Confession," and has made his "appeal "to the law and to the testimony." He also demonstrates why it was that many of the Reformers regarded the use of instrumental music in public worship as the "badge of Popery."