Of course there are many other arguments for the use of hymns, as, for instance, that the Psalms are unsuitable for New Testament worship, breathe a spirit of revenge, and so forth, which borders, we think, on blasphemy; or that, as we are at liberty to pray in our own words, so we must be at liberty to sing praise in our own words in answer to this is that our liberty depends altogether on God’s revealed will, not on what we may think reasonable and further, that men were at liberty to pray in Old Testament times in their own words, but were required to employ only authorized psalmody in praise; and there is no reason for change in the matter now, and no reason for supposing that men are able now to frame suitable ones of praise, when they were considered so unable then that God furnished them with songs from heaven. Besides when people sing a hymn, they are not singing in their own words, but in the words of the hymn-writer, or in the words of an ecclesiastically authorized hymn-book. And if congregations are to take words other than their own in any case, one would think they would be safer with God’s words than with man’s.
~ James Dick, ‘Hymns and hymn-books’ in Original Covenanter, iii, no. 12 (Dec. 1883), pp 357-8.