Like most historic reformed churches, worship centres on the reading and preaching of the Bible, with the response of the people to God in praises, prayer and giving. Two areas of distinctiveness in the matter of praise are that the only words used in singing are from the Book of Psalms and that no instrumental accompaniment is used. This is the original practice of Presbyterian churches, which the Reformed Presbyterian church, alone in Ireland, maintains to this day. Her rationale, however, is deeper than loyalty to a historic tradition. Since God has revealed in Scripture how he is to be worshipped, nothing is to be introduced which he has not specifically commanded. Nowhere has he instructed his people to praise him with songs other than those provided in the Book of Psalms. Instrumental music was an integral part of Old Testament sacrificial worship, which was fulfilled in Christ, and there is no example of such accompaniment in the church of the New Testament.
The Book of Psalms provides songs which are inspired, Christ-centred, timeless, non-sectarian and continually relevant, the property of the universal church. Reformed Presbyterians experience profound spiritual fulfilment in singing, usually in four-part harmony, these glorious praises. The basic version used is the Scottish Metrical Psalter, with supplementary alternative versions. The Church has just completed a major process of Psalter revision.