The Westminster Assembly and Psalm-singing
Westminster Confession 21:5: "The reading of the Scriptures with godly fear; the sound preaching, and conscionable hearing of the word, in obedience unto God, with understanding, faith, and reverence; singing of psalms with grace in the heart [Col. 3:16; Eph. 5:19; James 5:13]; as also the due administration and worthy receiving of the sacraments instituted by Christ; are all parts of the ordinary religious worship of God: besides religious oaths and vows, solemn fastings, and thanksgivings upon special occasions, which are, in their several times and seasons, to be used in a holy and religious manner."
Westminster Directory for Public Worship of God: "Of Singing of Psalms. It is the duty of Christians to praise God publickly, by singing of psalms together in the congregation, and also privately in the family. In singing of psalms, the voice is to be tenably and gravely ordered; but the chief care must be to sing with understanding, and with grace in the heart, making melody unto the Lord [Col. 3:16; Eph. 5:19]. That the whole congregation may join herein, every one that can read is to have a psalm book; and all others, not disabled by age or otherwise, are to be exhorted to learn to read. But for the present, where many in the congregation cannot read, it is convenient that the minister, or some other fit person appointed by him and the other ruling officers, do read the psalm, line by line, before the singing thereof."
David Dickson (1583-1663) Scottish Presbyterian and author of the first commentary on the Westminster Confession: "Is singing of psalms with grace in the heart, a part of the ordinary worship of God? Yes (Col. 3:16; Eph. 5:19; James 5:13). Well then, do not the Quakers, and other sectaries, err, who are against the singing of psalms, or at least tie it only to some certain person, others being excluded? Yes. By what reasons are they confuted? 1st, From the practice of Christ and his apostles (Matt. 26:30). Form the example of Paul and Silas (Acts 16:25). Form Moses and the Israelites (Ex. 15). 2nd, Because the singing of psalms was commanded under the Old Testament, and that, not as a type of any substance to come, nor for any ceremonial cause Neither is it abrogated under the New Testament, but confirmed (Ps. 30:4; 149:1). 3rd, From the general and universal commands in the New Testament (Eph. 5:19; Col 3:16; I Cor. 14:15). 4th, Because the apostle James says, 'Is any man afflicted, let him pray; is any man merry, let him sing psalms (James 5:13). The meaning is not, that none should sing bus such as are merry; for then none should pray but such as are afflicted. 5th, Because by singing of psalms we glorify God, we make his praise glorious; we edify others with whom we sing as well as we edify ourselves. So the end to be proposed in singing is teaching and admonishing one another, in psalms, and hymns, and spiritual songs (Col. 3:16). Lastly, We cheer and refresh ourselves by making melody in our hearts to the Lord, (Eph. 5:19). Which ariseth, first, from our conscientious going about it as a piece of the worship to God, and in so doing we are accepted in that. Secondly, From its being a part of Scripture appointed for his praise, whether it agree with our case or not. That being the end wherefore it was designed to be sung, is sufficient warrant for our joining in the singing thereof" (Truth's Victory Over Error: A Commentary on the Westminster Confession of Faith by way of Question and Answer [Australia: Presbyterian's Armoury Publications, repr. 2002], pp. 119-120).
Robert Shaw (1795-1863) Scottish Presbyterian: "Singing of psalms. This was enjoined, under the Old Testament, as a part of the ordinary worship of God, and it is distinguished from ceremonial worship (Ps. 69:30-31). It is not abrogated under the New Testament, but rather confirmed (Eph. 5:19; Col. 3:16). It is sanctioned by the example of Christ and his apostles (Matt. 26:30; Acts 16:25). The Psalms of David were especially intended by God for the use of the Church, in the exercise of public praise, under the former dispensation; and they are equally adopted to the use of the Church under the present dispensation. Although the apostle insist much upon the abolition of ritual institutions, they give no intimation that the Psalms of David are unsuitable for gospel-worship; and had it been intended that they should be set aside in New Testament times, there is reason to think that another psalmody would have been provided in their room. In the book of Psalms there are various passages which seem to indicate that they were intended by the Spirit for the use of the Church in all ages. ‘I will extol thee, my God, O King,’ says David, ‘and I will bless thy name for ever and ever’ (Ps. 145:1). This intimates, as the excellent [Matthew] Henry remarks, ‘that the Psalms which David penned should be made use of in praising God by the Church to the end of time.’ We ought to praise God with our lips as well as with our spirits, and should exert ourselves to do it ‘skilfully’ (Ps. 33:3). As this is a part of public worship in which the whole congregation should unite their voices, persons ought to cultivate sacred music that they may be able to join in this exercise with becoming harmony. But the chief thing is to sing with understanding, and with affections of heart corresponding to the matter sung (Ps. 47:7; I Cor. 14:15; Ps. 108:1)" (An Exposition of the Confession of Faith [Scotland: Christian Focus Publications, repr. 1973], pp. 224-225).
G. I Williamson, American Presbyterian: "[An] element of true worship is 'the singing of psalms with grace in the heart.' It will be observed that the Confession [21:5] does not acknowledge the legitimacy of the use of modern hymns in the worship of God, but rather only the psalms of the Old Testament. It is not generally realized today that Presbyterian and Reformed Churches originally used only the inspired psalms, hymns and songs of the Biblical Psalter in divine worship, but such is the case. The Westminster Assembly not only expressed the conviction that only the psalms should be sung in divine worship, but implemented it by preparing a metrical version of the Psalter for use in the Churches … we must record our conviction that the Confession is correct at this point. It is correct, we believe, because it has never been proved that God has commanded his Church to sing the uninspired compositions of men rather than or along with the inspired songs, hymns and psalms of the Psalter in divine worship" (The Westminster Confession of Faith for Study Classes [Philadelphia: P & R, 1964], p. 167).
Frank J. Smith, American Presbyterian: "The Westminster Confessional Standards, considered by many the greatest confessional creed ever written, prescribe exclusive psalmody" (Worship in the Presence of God, eds. Frank J. Smith and David C. Lachman [Greenville, South Carolina: Greenville Seminary Press, 1992], p. 224).