It's hard to imagine hymns as something new, daring or even mildly subversive but, once upon a time, they were not only a novelty but their use in parish churches were almost illegal! Until the early 18th century, most congregations sang almost nothing but metrical psalms in the "Old Version" dating from 1562. They also used a very limited number of tunes!
The new hymns were seized on with enthusiasm by John Wesley and his brother Charles who made hymn-singing an important feature of their ministry. The Wesleys' appeal was largely to the working classes and their hymns were often used in large open-air meetings.
The Methodists soon began to write new tunes for their hymns in an unashamedly secular style which would not have been out of place in the theater, the pleasure gardens, or even (oh, my!) the tavern. This truly shocked the Establishment and delayed the introduction of hymns into parish churches. Such was the popularity of hymn-singing however, that by the end of the century it was widespread in nearly all denominations.
Given that we're coming upon the Advent season, with all the beautiful hymns that we sing for such a short period of time, let us not forget "John Wesley's Instructions for Singing (1761)"!
I. Learn these tunes before you learn any others; afterwards learn as many as you please.
II. Sing them exactly as they are printed here, without altering or mending them at all; and if you have learned to sing them otherwise, unlearn it as soon as you can.
III. Sing all. See that you join with the congregation as frequently as you can. Let not a single degree of weakness or weariness hinder you. If it is a cross to you, take it up, and you will find it a blessing.
IV. Sing lustily and with good courage. Beware of singing as if you were half dead, or half asleep; but lift up your voice with strength. Be no more afraid of your voice now, nor more ashamed of its being heard, than when you sung the songs of Satan.
V. Sing modestly. Do not bawl, so as to be heard above or distinct from the rest of the congregation, that you may not destroy the harmony; but strive to unite your voices together, so as to make one clear melodious sound.
VI. Sing in time. Whatever time is sung be sure to keep with it. Do not run before nor stay behind it; but attend close to the leading voices, and move therewith as exactly as you can; and take care not to sing to slow. This drawling way naturally steals on all who are lazy; and it is high time to drive it out from us, and sing all our tunes just as quick as we did at first.
VII. Above all sing spiritually. Have an eye to God in every word you sing. Aim at pleasing him more than yourself, or any other creature. In order to do this attend strictly to the sense of what you sing, and see that your heart is not carried away with the sound, but offered to God continually; so shall your singing be such as the Lord will approve here, and reward you when he cometh in the clouds of heaven.
Now, let the hymn singing begin!