The Reformed Presbyterian Church believes that every form of worship not commanded by God is forbidden. This ‘Regulative Principle’ is in line, we believe with the clear teaching of the Bible, as well as The Westminster Confession of Faith XXI.II.

In the Old Testament, there is no record of a musical instrument ever being used in public worship without an explicit divine command. In the New Testament, we are commanded to, through Christ, ‘continually offer up a sacrifice of praise to God, that is, the fruit of lips that acknowledge his name’.

The use of musical instruments was unknown to the church up till the 13th century, didn’t receive general acceptance till the 14th and 15th centuries - and it was promptly wiped out again by the Reformation. Only two of the Reformation and Puritan leaders, Martin Luther and Richard Baxter, were in favour of instruments, and neither believed in the Regulative Principle.

As John Calvin wrote, “To sing the praises of God upon the harp and psalter unquestionably formed a part of the training of the law and of the service of God under that dispensation of shadows and figures, but they are not now to be used in public thanksgiving.”

Read more:
John Price, Old Light on New Worship: Musical instruments and the worship of God, a theological, historical and psychological study (Avinger: TX: Simpson Publishing Company, 2005)
Brian Schwertley, Musical Instruments in the Public Worship of God
John L Girardeau, Instrumental music in the public worship of the church (Richmond: VA, 1888)
Malcolm H. Watts and David Silversides, The Worship of God (Edinburgh: Marpet Press, 1998). audio version online here