…when we think how public worship should be constructed and what methods should be employed in the praise of God and the edification of his people, “such means are to be desired, as have much of a tendency to move the affections. Such books, and such a way of preaching the Word, and administration of ordinances, and such a way of worshiping God in prayer, and singing praises, is much to be desired, as has a tendency deeply to affect the hearts of those who attend these means.”
And this to say about worship styles:
When people object that certain styles of public worship seem especially chosen for their capacity to awaken and intensify and express the affections of the heart, they should be told that such is precisely the God-ordained purpose of worship. What they fear – namely, the heightening and deepening of the heart’s desire and love for God, and the expansion and increase of the soul’s delight and joy in God, what they typically call “emotionalism” or even “manipulation” – is the very goal of worship itself. For God is most glorified in his people when their hearts are most satisfied in him.
And this to say about singing in worship:
Consider…the singing of praises to God, which seem to be “appointed wholly to excite and express religious affections. No other reason can be assigned, why we should express ourselves to God in verse, rather than in prose, and do it with music, but only that such is our nature and frame, that these things have a tendency to move our affections.” We sing because God has created not only our minds but also our hearts and souls, indeed our bodies as well, in such a way that music elicits and intensifies holy affections for God and facilitates their lively and vigorous expression.