In this Christmas classic, the angels are hearkening the birth of Christ, the newborn king. The song tells an abbreviated but very spirited version of the Gospel story.
The words to "Hark! The Herald Angels Sing" were written by Charles Wesley, the brother of the founder of Methodism John Wesley. He was inspired by the sounds of London church bells while walking to church on Christmas Day. The poem first appeared in Hymns and Sacred Poems in 1739 with the opening line of "Hark, how the welkin (heaven) rings." Wesley's evangelist colleague, George Whitefield, altered it to the familiar opening line over the protests of the author in 1753.
Then in 1760 the Reverend Martin Madan changed lines 7 and 8 from:
Universal nature say
Christ the Lord is born today
To What we know today:
With the angelic hosts proclaim
Christ is born in Bethlehem!
The song went through various other adaptations over the years.
The tune was originally composed by Felix Mendelssohn in 1840 for the second chorus "Gott ist Licht" ("God is Light"), of the cantata Festgesang ("Festival Song"). Festgesang was written by the German composer to commemorate Johann Gutenberg and the invention of printing. Mendelssohn died in 1847 and in 1855 Dr. William Cummings, who was an enthusiast of the German composer, put the words and music together in spite of the fact that Mendelssohn had made it clear that his music was not be used for sacred purposes. Additionally, Wesley had envisaged his words being sung to the same tune as his Easter hymn, "Christ the Lord is Risen Today." However it is Mendelssohn's tune that is generally used today.
"Hark!" was a popular term in the time this song was written. It was used before speaking to let the listener know that an important message is forthcoming - a modern equivalent would be "Listen Up!" In this case, the angels have important news to share, so they are prefacing it with "hark!"
Charles Wesley was a prolific hymn writer, penning over 6000 hymns, more than any other male writer. (Fanny Crosby wrote 8000). Wesley had the ability of expressing sublime truth in simple ways, his motivation in writing his hymns being to teach the poor and illiterate good doctrine. His brother, John Wesley, said that Charles' hymnal was the best theological book in existence. It is said Methodism was born in song and Charles was the chief songwriter. Among the hymns Charles Wesley wrote were, "O For A Thousand Tongues," "Love Divine All Loves Excelling" and "Jesus, Lover of my Soul."
There are two additional verses in the original version of this song that George Whitefield removed:
Come desire of nations come
Fix in us thy humble home
Rise the woman's conquering seed
Bruise in us the serpent's head
Now display thy saving power
Ruin'd nature now restore
Now in mystic union join
Thine to ours and ours to thine
Adam's likeness Lord efface
Stamp thy image in its place
Second Adam from above
Reinstate us in thy love
Let us thee though lost regain
Thee the life the inner man
O to all thyself impart
Form'd in each believing heart