Reading the introduction to this hymn book is instructive for those of us who seek to participate in Christian music. In particular, I would like to call attention to the following paragraph:
There is a style and manner suited to the composition of hymns, which may be more successfully, or at least more easily attained by a versifier, than by a poet. They should be Hymns, not Odes, if designed for public worship, and for the use of plain people. Perspicuity, simplicity and ease, should be chiefly attended to; and the imagery and coloring of poetry, if admitted at all, should be indulged very sparingly and with great judgment. The late Dr. Watts, many of whose hymns are admirable patterns in this species of writing, might, as a poet, have a right to say, That it cost him some labor to restrain his fire, and to accommodate himself to the capacities of common readers. But it would not become me to make such a declaration. It behoved me to do my best. But though I would not offend readers of taste by a wilful coarseness, and negligence, I do not write professedly for them. If the LORD whom I serve, has been pleased to favor me with that mediocrity of talent, which may qualify me for usefulness to the weak and the poor of his flock, without quite disgusting persons of superior discernment, I have reason to be satisfied.
I love how, in comparing himself to Isaac Watts, he speaks of limiting the poetic elements so that the hymn communicates to "plain" people. The first task for the hymn writer, according to Newton, is clarity of communication, which requires simplicity and ease of access.
Of course, he isn't suggesting that the banal and crass should be fair game, and this is clear in how he describes his need to do his best and in how he disavows "willful coarseness." In contrast, he describes Watts as needing to temper his poetic gifts in order to produce a text that is good for the whole congregation.
Basically, he hopes not to "offend the readers of taste" but avows that he isn't writing for them. He hopes to write in such a way as to be useful to the congregation as a whole, without intentionally offending those with "superior discernment."
In essence, he is content to communicate the truth clearly, in verse, so that it is transparent to everyone without at the same time offending those who would have higher taste. I appreciate this sentiment greatly, since we hope to communicate clearly, without offending those who are truly gifted musicians and writers. I am a preacher first, and music is helpful in that the clarity of an exposition can often be enhanced by an accompanying song.
Newton understood this, which is why you will find a virtual commentary in song, along with hymns that are marked "before the sermon" and "after the sermon." Newton appreciated the value of music that preaches.