Song: Hark the herald angels sing

In the popular animated Charlie Brown Christmas special (1965), Linus explains the true meaning of Christmas by reading from scripture. Charles Shultz insisted that the Bible reading be included. On a short timeline, the network agreed.

Luke 2:13 And suddenly there was with the angel a multitude of the heavenly host praising God, and saying, [kjv]

2:14 Glory to God in the highest, and on earth peace, good will toward men. [kjv]

There is one angel mentioned and a multitude of heavenly host. Where do we get the idea that the angels sang it the birth of Jesus?

Luke 2:13

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KJV: And suddenly there was with the angel a multitude of the heavenly host praising God, and saying,

Greek: και εξαιφνης εγενετο συν τω αγγελω πληθος στρατιας ουρανιου αινουντων τον θεον και λεγοντων

Wycliffe: And sudenli ther was maad with the aungel a multitude of heuenli knyythod, heriynge God,

Tyndale: And streight waye ther was with the angell a multitude of hevenly sowdiers laudynge God and sayinge:

Luke 2:14

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KJV: Glory to God in the highest, and on earth peace, good will toward men.

Greek: δοξα εν υψιστοις θεω και επι γης ειρηνη εν ανθρωποις ευδοκια ευδοκιας

Latin: gloria in altissimis Deo et in terra pax in hominibus bonae voluntatis

Wycliffe: and seiynge, Glorie be in the hiyeste thingis to God, and in erthe pees be to men of good wille.

Russian: слава в вышних Богу, и на земле мир, в человеках благоволение!

Luke 2:15

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KJV: And it came to pass, as the angels were gone away from them into heaven, the shepherds said one to another, Let us now go even unto Bethlehem, and see this thing which is come to pass, which the Lord hath made known unto us.

Greek: και εγενετο ως απηλθον απ αυτων εις τον ουρανον οι αγγελοι και οι ανθρωποι οι ποιμενες ειπον ελαλουν προς αλληλους διελθωμεν δη εως βηθλεεμ και ιδωμεν το ρημα τουτο το γεγονος ο ο κυριος εγνωρισεν ημιν

Bethlehem, in Hebrew, means "House of Bread". Who is the "bread of life"?

Luke 2:13 And suddenly there was with the angel a multitude of the heavenly host praising God, and saying, [kjv]

… αγγελω … στρατιας … αινουντων … λεγοντων [gnt]

2:14 Glory to God in the highest, and on earth peace, good will toward men. [kjv]

δοξα εν υψιστοις θεω και επι γης ειρηνη εν ανθρωποις ευδοκιας [gnt]

Charles Wesley (1707-1788) wrote: "Hark the herald welkins ring".
George Whitefield (1714-1770) changed it to: "Hark the herald angels sing".
Felix Mendelssohn (1809-1847) wrote music, also "Wedding march".

Ever since, angels have been singing at Christmas in songs, devotionals, etc.

The German word "die Wolke" ≈ "the cloud" which is related to the Old English word "welcan" ≈ "cloud".

Luke 2:14 Glory to God in the highest, and on earth peace, good will toward men. [kjv]

δοξα εν υψιστοις θεω και επι γης ειρηνη εν ανθρωποις ευδοκιας [gnt]

The Greek for "glory" is that of "opinion" or "expectation".
The Greek for "good will" is that of "good opinion" or "good expectation".

Paraphrase: Expectation/opinion in the highest (from earth) to God and on the earth peace in men of a good expectation.

God has a high opinion and a good expectation that men will be peaceful on earth. To support the KJV (King James Version) translation, the second Greek "in" is to the English "towards". To support the Greek "in", translations like the NIV (New International Version) use the following.

NIV: Glory to God in the highest heaven, and on earth peace to those on whom his favor rests.

The song "Hark the herald welkins ring" was written by Charles Wesley (1707-1788), who helped found the Methodists and who wrote thousands of hymns.
The "welkin" is the heaven or sky or cloud. George Whitfield, a co-founder of Methodism, changed the words that Charles Wesley, a co-founder of Methodism, had written.

Wesley: "Hark the herald welkins ring"
Whitfield: "Hark the herald angels sing"

Wesley was not happy. Ever since, songs have the angels singing even though this is not found in the Bible (except in part of Revelation).

The word "welkin" is used numerous times by Shakespeare.

[King Richard to his army] Amaze the welkin with your broken staves! [Richard III]
[Titus to Lavinia] with our sighs we'll breathe the welkin dim. [Titus Andronicus]

In English, the word "cloud" eventually replaced "welkin".
The German word "die Wolke" ≈ "the cloud" is related to the Old English word "wolcne" ≈ "cloud" and the Old English word "welcan" ≈ "cloud" which is the source of "welkin" as used by Wesley.

More: William Shakespeare

Matthew 17:5 While he yet spake, behold, a bright cloud overshadowed them: and behold a voice out of the cloud, which said, This is my beloved Son, in whom I am well pleased; hear ye him. [kjv]

… νεφελη … νεφελης … [gnt]

At the transfiguration, the following is recorded.

Matthew 17:5

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KJV: While he yet spake, behold, a bright cloud overshadowed them: and behold a voice out of the cloud, which said, This is my beloved Son, in whom I am well pleased; hear ye him.

Greek: ετι αυτου λαλουντος ιδου νεφελη φωτεινη επεσκιασεν αυτους και ιδου φωνη εκ της νεφελης λεγουσα ουτος εστιν ο υιος μου ο αγαπητος εν ω ευδοκησα αυτου ακουετε αυτου

Latin: adhuc eo loquente ecce nubes lucida obumbravit eos et ecce vox de nube dicens hic est Filius meus dilectus in quo mihi bene conplacuit ipsum audite

Wessex: hym þa gët sprecende. & soðlice þa briht-welcan hyo ofer-scan. & þa efne com stefen of þam wolcne & cwaeð. Her ys min leofe sunu. on þan me well ge-likað. ge-hereð hine.

Wycliffe: a briyt cloude ouerschadewide hem; and lo! a voice out of the cloude, that seide, This is my dereworth sone, in whom Y haue wel pleside to me; here ye hym.

Luther: Da er noch also redete, siehe, da überschattete sie eine lichte Wolke. Und siehe, eine Stimme aus der Wolke sprach: Dies ist mein lieber Sohn, an welchem ich Wohlgefallen habe; den sollt ihr hören.

George Whitfield, a co-founder of Methodism, preached in 1740 in what has been called the "Great Awakening". He changed the title from "Hark the herald welkins ring" to the ever since popular Christmas carol "Hark the herald angels sing". Charles Wesley was not happy as he asserted that there is no verse in the Bible for which the angels sing at the birth of Jesus. But the change remained. But the floodgates were open and there was no stopping it. To this day, when you hear a Christmas carol that whose lyrics have angels singing at Christmas, that carol was written after the original song title "Hark the herald angels sing".

Who is Charles Wesley? (1707-1788)
What is a "welkin"? (used by Shakespeare)
Who is George Whitfield? (1714-1770)
Who is Felix Mendelssohn? (1809-1847)

Hark! the herald angels sing , Glory to the new-born King
Peace on earth and mercy mild, God and sinners reconciled

Joyful, all ye nations, rise, Join the triumph of the skies
With angelic host proclaim, Christ is born in Bethlehem

Hark! the herald angels sing, Glory to the new-born King

What is an "angel"? (as found in the Bible)
What did the angel(s) do above the fields of Bethlehem on Christ's birth?

Those fields could have been the same fields of Ruth and Boaz (grandparents of King David).
In the time of Jesus, Bethlehem was a source of sacrificial lambs for the Passover sacrifices in Jerusalem, about 6 miles away.
How do we know what the angels did above the fields of Bethlehem that night?

From the beginning sentence of the introduction on page 3 of the pamphlet entitled "Glory to God in the Highest: Devotions for Advent" by Chad Bird we read the following.

When the angels sang, "Glory to God in the highest," they didn't send the shepherds to a high place but a low one.

Did the angels really sing?

Christ, by highest heaven adored
Christ, the everlasting Lord
Late in time behold him come
Offspring of the Virgin's womb
Hail the Flesh, the God Head see

Hail the incarnate Deity
Pleased as man with man to dwell
Jesus, our Emmanuel!
Hark! the herald angels sing
Glory to the new-born King

Hail the Heaven-born Prince of Peace
Hail the Son of Righteousness
Light and life to all He brings
Risen with healing in His wings
Mild He lays His Glory by

Born that man no more may die
Born to raise the sons of earth
Born to give them second birth
Hark! the herald angels sing
Glory to the new-born King